Since they're both legally adults, there's nothing anyone can do. My close friend has always had a Savior's Complex. This woman that he has recently gotten involved within the past year has accused several men of a serious crime they didn't commit. Our mutual friends are afraid the same will happen to him and some have warned him. He claims to be just friends with her but at the same time treats her like a girlfriend including staying overnight at her place. The woman has 6 different mental disorders.... And because of their age difference, with him being easily old enough to be her father, it almost feels like he's preying on her vulnerabilities. She's still very young, just entered adulthood few years ago. It just seems like a disaster in the making.
My close friend has a no criminal history, his own home, and full-time job. It breaks my heart to watch him risk it all over a woman who can't be helped. There's a reason she's has a Guardian who watches after her. She's mentally ill.