My friend has a ton of health issues, including a tumor in his neck and several other things. He got a bad stomach bug thing, and he took his temperature it was a 94.3 should he be worried? Or is it just a bug that will pass?

Too many factors, it could be a bug, but of course with a multiple health issues, it could be any of them also. If it was me, I would see the doctor, only he can make that choice