Not the cause, but....
A major precipitating risk factor certainly. His atherosclerosis was shown to be very severe at autopsy (as you will have read, markedly affecting arteries in the brain, his aorta, coronary and renal arteries). Such widespread atheroma can lead to a number of problems and in a sense it was waiting to kill him. His smoking and drinking would have contributed in part to this. It is hard to tell how much of a part these facts had to play, and there may have been other factors including genetic ones.
Atherosclerosis is worryingly common here in the UK and other Western countries, where our lifestyle no doubt increases the prevalence of vascular disease.
Have another go, you’re on the right track.