How do I convince him to go to the doctor?

I am at my wit's end. He (my boyfriend) got a cold a year ago and never shook the cough. It's a dry cough and it stayed around. Now he got another cold on top of it and the cough got worse. He refuses to go to the doctor unless, and I quote: "I have a heart attack or my head explodes".

Yesterday he said he tasted blood at the bottom of his throat, though none visible. He still refuses to go to the doctor and every time he coughs it feels as though someone is dragging a pitchfork over his lungs.

How do I convince this man to go see a doc before he actually starts spitting blood?!

Pleeease help!!!

P.S: he is not a smoker and he's never had lung problems before.