I'm surprised that your dog has bit 4 people in the manner he did and is still allowed to be in your home. Is that because they are your family members and the bites weren't reported?
I know my opinion is not a popular one here, but my kids come before pets, especially one that bites unprovoked. I would also be very fearful of lawsuits.
BUT I do not have the time or ability to do the behavior training necessary to retrain an aggressive dog. That factors into what my decision would be- that I would be returning the dog to the rescue agency and letting them know why and hope they can place him with someone better equipped than I am.
I agree with fryjack2 . I would not be able to trust a dog that bit even with behavioral therapy.
Same.
I hate to say it, but I wouldn't want to spend the $$$ on behavioral therapy considering it may not work. Honestly, he's been aggressive in multiple situations that were completely different. Unless you can completely reprogram a dog, I don't think I'd be able to relax with him around my family or other people. That's just an accident - and a lawsuit - waiting to happen.
I have fostered with several animal rescues. Just curious if you have contacted the rescue to see if they can provide any assistance? No rescue wants an adoptive family to be in this situation and I'm sure they would be willing to help you. Some rescues have trainers on call who can take the dog for temporary "board and train" just to give everyone a break from the situation and to determine if the adoptive home is the best fit for the dog. I also think at this point after 2 visits that I would have the vet muzzle the dog to do a full vet check to make sure there is nothing medically wrong, or consider a home vet visit where the dog can be less stressed. I'm sorry you're going through this - it sounds really stressful.