First of all, kudos to you for taking in this baby. Think of all he's
been through in his short life--probably a lot. He's just had a
traumatic experience and needs time to recover. Give him lots of love
and attention and he will come around. If he doesn't like you to touch
him, talk to him softly and play with him. Get a couple of Feliway
diffusers and plug one in his room and the other where Jack is to ease
the tension. You can also play talk radio softly in the room while
you're away.

Keep reaching out. He'll come around.