Oh my god, I am so sorry to hear about your boy
Unfortunately nothing can bring the poor soul back, but I'm pretty sure that it wasn't choking that made him die so please don't blame yourself.
Was the vet not able to shed any light onto the cause?
I know you feel like locking yourself away and crying but I would highly reccommend that you call your breeders and talk to them about it. Maybe they have had something similare happen before and especially if god forbid any of Wolf's litter brothers & sisters have the same they can hopefully get to the vets with more information.
My thoughts are with you at this sad time. Wolf was obviously only meant to be with you for a very short time, but hopefully his passing won't stop you from offering another dog in the future a loving home.
Take care xxxx