How do I break up with him? He claims he'll die...?

look, no one deserves that crap. talk to his family and tell them your situation and then break up with him for good. DO NOT get back with him.. or talk to him for that matter. make sure he knows that there is NO chance of you two getting back together. it'll be tough but him using the fact that he'll "die" is selfish and retarted. be happy. live life.