Most likely a combo of Vasari LRFs and carriers with bombers. LRFs target the Kols and the carriers (with their bombers safely in their bays) hold to attack until after the Kols are mostly done for. Also the Vasari can get their own help in supply points (phasic communications I believe under civilian or whatever the Vasari use) to help equalize this.

Sounds like the primary issue is that he has a far more advanced and powerful empire, and exactly what kind of units he's using is more or less irrelevant.  You'd be equally screwed if those were Javelis LRM or Carriers.  With such a severe numerical advantage, TEC is going to be very difficult to beat regardless of what he's doing.  Instead, you need to focus on your early game to better match his advancement and progress, and pressure him so he can't get his ideal economy running.  If you can match him for numbers, TEC is a lot less intimidating in the late-game.

That fleet is actually quite weak and poorly structured given its cost, so it really sounds to me that your big problem is being outnumbered.  He's got way too many capital ships for how many frigates he has, and he has no hoshikos.  He could make that a lot stronger just by choosing slightly different unit proportions.  Basically, the battle was over before the first shots were fired, and he doesn't even need to play seriously at this point to beat you.

The one thing I will suggest is to lean heavily on the Stikulus Subverter against HC-based fleets.  This support cruiser can disable large numbers of enemy units, and the relatively short-range of the heavy cruiser causes them to cluster up a bit and renders them vulnerable to this shutdown.  This can remove a lot of the enemy's firepower while simultaneously preventing them from retreating.  Absolutely brutal in the hands of an expert, and something you definitely want to use.

This is going to take a long time for him to do, and if his fleet is small in the duration you should have more than sufficient window of opportunity to get your own competing economy operational and attack him before he even reaches the highest-tier economic upgrades.  What you need to be able to do is compete in the economic race until the opportunity comes to attack; TEC will have some advantages here, but you don't need to match him, just keep up.  If you can bring out a Vasari fleet about 80% his strength, that should be enough to give you a fighting chance.

The best recommendation I have is to stay lean and focus on colonizing rapidly.  You should be able to manage one new colony acquisition every 3 minutes on average.  You should cut back on technology and infrastructure to maintain your rapid colonization and a fleet to protect it.  As Vasari, rushing into more advanced stuff like refineries, broadcast centers, or trade ports is foolish.  Avoid investing heavily in defenses this early, since you want to push your borders forward. 

AI's, particularly at "hard" difficulty and below, are very slow, inflexible, and worthless as conventional allies.  I'd be more inclined to wipe them out in order to take their assets for myself and use their units as experience to level up my capital ships, keeping one alive for pacts.  You'll need to be able to stand on your own, expand faster, and get an economy rolling sooner.

Sry, I wasnt descriptive enough, his fleets arent only kols and HC, he has a few other caps as well as about 1:5 repair ships to HC's, as well as a good number of LRM's. The AI we play with are Unfair difficulty, so rushing them is tough since they cheat (HC's and carriers by their 3rd planet? yeah right). I simply have to get SB's up to counter AI rushes as well as OP early pirates. My next strat I will try is a couple Carrier caps, as well as maybe a few carrier-frigates with all bombers. I tend to avoid this cause 15-30 fighters will slaughter almost any number of bombers along with the Kol's. 

Basically, rushing is too difficult when I have to worry about early game AI and pirates, as well as us playing on Large/Huge maps. Maybe TEC just out-class Vasari in this scenario.

Okay, he's within the "sweet spot" for hoshiko proportions, and those LRM's are rock solid units as well.  If he's got a few gardas to round it out, then his only real issue is that he's capital ship happy.  Again, I reiterate that you need to focus your attention on the early-game to better keep up with him.

Diplomacy pirates are nasty business, and I'd really recommend turning them off.  If you insist on playing with them, your best bet is probably to sacrifice some strike craft just when the pirate raid is forming.  Send some fighters to fly over some militia gardas, which should get them killed in short order.  This will cause some of your bounty to deplete, reducing the chance of you being the pirate raid victim, and all the while draining bounty someone placed on you.  To top it off, it's not real damage; those strike craft are replaced for free anyways. 

Yeah, unfair is where the AI starts to get serious.  Still slow to react and inflexible, but their resource advantage is well worth your time and effort to befriend them.  Still definitely rushable; as Vasari try sneaking a starbase onto their homeworld.

Not necessarily.  Use some Sentinels to back up your bombers.  Manually maneuver your bombers to get the enemy fighters to fly over your sentinels.  If you have enough, you should kill the fighters faster than they can kill your bombers.  If you manually manage your attack runs to avoid putting too many bombers in Kol range at the same time, you can deal a lot of damage without exposing yourself to his full firepower.

While TEC does have an early-game advantage, Vasari has a significant late-game advantage.  The problem is that you're fall so far behind that you can never catch up and the TEC just rolls you.  The problem is you're being outplayed in the early-game, and that's where you need to focus on improving your game plan.

rush

One thing I would think is if you have the money send as big as you possibly can planet assisn mission for the pirates at his frigate factory planet.

Didn't exactly read all posts   but if he doesn't include ogrows en mase in his fleet 20 subverters 20 overseers and 4 Skirantra caps lvl3 or higher accompanied with fuly upgraded vasari SB and some phasic hangars and relevant phase missile research can beat any fleet that will fight in that gravity well. That is if you are good with microing and you know how is it possible to permanently disable his whole fleet.

4 level 3 skirantras can field 60 bombers and can replace them baster than kols can kite them or if kols run out of AM they are basically dead weight so I would first focus on kols so they dont get to lvl 6 or higher ......

PS

You could use phasic stabilizers to get 1 phase jump to every planet you own and you could go for returning armada which enables you to build no military labs at all to get high tier ships. Though I think 3 mil labs is a must for vasari player.

All you need to do is turtle up and hold them for long enough until you can get a fleet combo that is impossible for tec to destroy. Accompanied by kosutras ......

I tend to agree with Darvin that you are losing not because of specific fleet make up but because your friend has grown much bigger than you.  Based on what you say, he is using the AI as a buffer while using his economy to keep the pirates on you -- you have to spend money on defenses and slow your expansion while he grows unchecked.  By the time he is ready to fight you he is just steamrolling with a bottomless economy. 

It is kind of a funny thing about Sins, sometimes you have lost the game before you are even half done playing it out.  You need to either convince him to play 1v1's without pirates or figure out how you are going to make allies and have pirates work for you so you can have the same strategic advantage he is enjoying while he eco booms.  Vasari can often get a really strong resource based economy going if they can find some neutrals early on and invest in the resource techs.  Don't be afraid to sell this on the black market when you are making a lot more than you need to jump start your own economy.