Some things cannot be fixed. I urge you to get a qualified behaviorist (veterinary) to evaluate him. If he is truly unstable, rehoming him is not fair to him or the new home.
Oh no! Poor Quinn. The past few months have been rocky for him. You really are an amazing person for all you have done and continue to do for him. I'm sure he knows that he is loved now. Sending happy thoughts and hugs to both of you!
