I'm playing single player on a large map, 10 factions. 3 hard AIs, the rest are all normal. I've divided everyone into 4 teams, put a hard AI and myself on each team, and let the rest of the Normals fill up random spots. My team consists of Myself and one Normal AI. 

At the beginning of the game my ally unfortunately started off with a Hard AI neighbor, and from what i've seen he seems to be set as an Aggressor type.  For the first hour or so these two were fighting, but eventually things settled down into a stalemate where my ally controlled a mere 2 planets: his Terran Homeworld and an Asteroid. He managed to fortify enough with a Starbase and mines long enough for the Hard AI get bored and move onto bigger fights. My empire started off too far away to help him at all, but i was able to expand in my own region and now am pretty strong. 

So now the situation is this: I have a powerful fleet and have destroyed all the Hard AIs holdings within my teams' solar system, including the planets around my ally's homeworld. I have deliberately NOT colonised these planets, leaving him 7 or so worlds on which he can colonise at his leisure so that he can get an economy going and get back in the game. I'm hoping that later on he can help me take on all the other teams (there are still 5 more star systems to fight over). Unfortunately, he's just not colonising anything. There is no opposition at these worlds anymore, he has a couple of Colony frigates just hanging around, and now he has no enemies in the immiediate area because i've already wiped the floor with them. He also has NOT surrendered or anything. He's still in the fight. 

Is there anyway to coax my Ally to get moving again? It's like he's just depressed or something, tired of losing so many capital ships early game. I've tried telling him to attack these worlds, and he does, but once all the enemy structures are destroyed he just moves on, doesn't try colonising.