How can I get over dads death?

My fiance dad committed suicide when she was 12 yrs old. Since then she has never let that go and she is starting to self-destruct. She gets plastered and get abusive with me, cuts herself (at times), hits/throws herself around. How can I help her with this problem? I have tried to convince her to try a psychologist but she refuses. She uses the alcohol as a crutch and I need to fix this before she gets any worst.