I'm very relieved that Alvin doesn't have dental problems.
Although I can understand how difficult it is when your bun's guts stop working, there is no obvious reason for it, & you've done all the right things for him.
The temperature factor does make a lot of sense. My vets have said about it too.
Hoping for a very rapid recovery for Alvin, so he can get his Christmas nom noms.
and i hope you get good news about your little man soon, was just about to look for your thread for an update