I don't know what to do... what should I tell my friend?

its a tough one. but you have to remember that you cant really change anyones thinking, your best bet is to tell her "you do as you see fit, but i am always your friend and if you need me ill be here" thats the best you can do. you need to talk to someone about this girls death. i would suggest a counsellor or if you dont want to find someone you know who is not connected in any way to the person herslf. you are in a mild state if grief. this is not a bad thing but you need to work it through.