What do u do when you see the person you love making the same mistake over and over?

I really hate watching him suffer. I know he has not been taking meds for PE. Hes allergic to my cat but wont let me get rid of him cause he gave him to me. He says he cant breah but still smoking. Every time i say something he practically bite my head off. But im so worried cause the last time he thought he had cold he had to stay in the hospital for a week....i cant take this he makes me stress!!! I dont want nothing to hAppen to him. But how to make a stubborn man see a dr. Before hes passed out or worse and carried there?