I dont know what to do about my dad?

i'm 15 years old too. wow that stucks. my stepdad is like that too but he is also an alcoholic. your dad sounds pretty mean, especially the part about him wanting to have cancer. if you want to have a relationship with him, dont make any suggestions and only talk to him when he is in a pleasant mood. if you dont want anything to do with him, then just dont talk to him anymore. dont make him a part of your life