I've seen this several times on tv. I believe an episode I'm thinking of with Victoria Stilwell she said the dog was trying to protect the owner who was in a similar situation. I believe she had different people come in and treat the dog any time he wasn't aggressive, even if it was just for a few seconds so he realized other people weren't bad. I don't know where you can find episodes of "It's me or the dog" online, but i love it, it's a good show. Only thing is if I used that many treats on my dog he'd be a chunky monkey
So I try to treat with toys and affection. I have never really caught Ceasar's show, I wish I had DVR so I could see his methods. Good Luck!