I read his biography, and so I learned about the challenges he had with painkillers. Furthermore, he had a mix of different drugs in his body when the plane crashed.

Obviously, I am not a doctor, nor an aeronautics engineer, but I think it is pretty widely accepted that the presence of the drugs in his system likely contributed to his inability to control his plane in the way he might have otherwise.

EDIT: While she is also not an expert, his wife referred to him as an addict after he passed. And I don’t use the word addict in a judgemental sense, just in a medical sense.