He probably had it because of eating too many fatty foods. Foods high in Trans Fat
, and Saturated fat
cause a fatty block called an embolus in an artery. If it happens in the arteries that give the heart nutrients, then it's a heart attack
. If it happens in the brain, it's a stroke. If it happens in a muscle it's an infarction
If the doctors say he will be fine, trust their opinion.
Medicine isn't an exact science, and it's very difficult.