Why did my ball python die suddenly after head wobble, regurgitation?

So sorry to hear this happened. I hate to say it but often times snakes just die for no reason at all. Sometimes these animals are weak genetically or they had pneumonia and that caused them to be weak. It is not always outwardly obvious when they are sick.

If you want to know what happened get a necropsy (autopsy) done and request that the vet send tissue samples off to a pathologist. This might be costly, but if you want results that's the way to do it. Otherwise we are only speculating.

Here are some common differentials for why a snake would die suddenly:

1. Parasites (internal)
2. Dehydration/kidney failure
3. Heat disease
4. Vitamin/mineral deficiency
5. Stress
6. Viral disease

With the head wobble he may have had Stargazing syndrome which is not a disease in and of itself, but is a symptom of other disorders, the most important of which is a viral infection of boa constrictors and pythons called inclusion body disease. If I had to venture a guess I would say that he likely had inclusion body disease. Again, without some testing we likely won't know for sure.

Hope this helps. Again, so sorry this happened.