Wow that seems pretty severe. Just have to be patient, eventually he will realize you aren't going to harm him but it could take a while. You definitely want things calm and quiet vs kids running around making loud noises while you are handling him so I'd stick to night time. With a burm, it's completely normal to still have a feeding response after eating a couple days ago but it should be easy enough to shut it down with a gentle tap of the hook if he isn't completely empty.