As mentioned by others, force feeding is a last resort and is often not necessary. Non feeding BP are usually a direct result of improper husbandry. BP MUST have all their needs met properly if you want them to eat. Mouse pinkies are not a good food choice for BP.
IF the snake's neck was broken like your roommate claims, then necropsy is the way to go. HOWEVER, It's important to understand that necropsies are ideally done in roughly 24 hours on an animal that had deceased. Anything longer than that can prove to be difficult, as autolysis (decomposition) runs its course.
It's really hard to tell what truly happened as there are a lot of variables here (one side of story, health of snake at pet smart, etc). HOWEVER, if your roommate's BP suffer cervical dislocation (medical lingo for broken neck), then the snake would have died immediately. In fact, that's considered an acceptable form of euthanasia for snakes up to a certain size.
Re: vet: it sounds like that vet was not a herp vet or at least one that was knowledgable on BP.
Now if the snake had a blockage as your roommate claims, then it would have had to see a herp vet regardless.
This is a case where both parties are at fault. Probably not what you want to hear. Use this experience as a lesson learned for next time. Before acquiring ANY animal, people need to do their research on the species they are looking to acquire.
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