Okay, Ranger & I both looked at this. The fixes you put in before the rollback are no longer in.
Not only does Tren not run away, but he stands around letting you pick him up and return him all the time, whether or not your partner is talking to his mother.
Also, couple of improvement to the quest occur to me.
1.) When I walked into the room where Tren was being kept, he started attacking the kidnappers he could see. Is he invulnerable and, if so, and might it not be interesting to have him at risk of being killed? Adds an element of danger to the quest that can't be ignored by having a High AC and hitting hard.
2.) Perhaps in the first conversation with Tren, you could "show him the portrait" as proof you came from his mother