Schizophrenic sister

Hi all. My sister is 42 and she is schizophrenic. She never steps out of home. She also chops off her hair and always carries a knife. Whenever she gets a new dress she tears down old dress. She keeps on destroying stuffs in house. She has been behaving crazy since her teens. She also doesn't cooperate to visit doctor. I live in another city and whenever I visit her she abuses me with mindless cursing. She stays with my mother who is getting old n this is worrying me too much. Any advice will be helpful.