Ex living in lala land?

My ex and mother of my son is living in a completely fictional world. she tells people she is abused but she isnt. she drinks heavily and smokes(cannibis i believe). she makes up all sorts of stories in her head then tortures my elderly grandmother with lies-she says me and my wife abuse her,she has called police numerous times. she has make believe conversations on the phone and is basically a sick and twisted woman. we know she has a history of mental illness-but now its impacting on my son and my family-some of the things she accuses us of could actually really cause alot of trouble-how can we get her the help when she wont accept she has a proble???