I definetly feel it would be possible for him to calm down. By the behaviour your describing it sounds like when you handle him he gets really stressed and tries to hide. Maybe if you wear something like a hoodie and let him hide in the pouch it would calm him down a bit and he could just sit in there but still be getting used to the human contact. Idk if that would even work, just a thought. On the other hand he may very well never calm down and you just have to love him for who he is haha