In the series Halloween, How did Dr. Loomis die. I know he died in the 6th installment but how?

He dies toward the end of the movie in part 6! I think its because michael myers kills him, or he has a heart attack! They dont show it but you hear him scream, Donald Pleasence died shortly after filming was completed, and rather than re-cast his character with someone else they re wrote it so that his character was killed off, that and the director was an idiot who thought Donald Pleasence wasn't important so he cut alot of his dialogue and scenes.