Well at least now you know...you don't let them take care of him again. Some people just do not have the patience for pets. Sad for them, but you can't let Charlie go through that again.
Give him some time, work hard to show him that he is back with ya'll and very, very safe. That accidents will not call down the wrath of the gods on him. Lots of positive reinforcement, calm low voices, careful movements.
As for his being standoffish to your DH. My guess would be that your FIL is the one who most yelled and "disciplined" him. So he's, understandably so, weary of men. Have your DH be his total care giver for several days and I bet you'll see him change back to loving his Daddy. All food, treats, play, walks, affection should come from DH. As hard as it will be on you, do your best to let DH be Charlie's world. We did this when I got married and DH moved in and it was just what the girls needed to see him in a positive light.
Good luck and let us know how it goes.
