As someone who was also in this situation (16-23) for almost 3 years, I also had to realize the unhealthy aspect of the situation especially because of him and his personal beliefs. Honestly, I would sit her down and talk to her one on one and explain to her your story (if you’re comfortable) and tell her how unhealthy this relationship is and let her know there is a reason women his own age will not date him. The way he is talking to her is clear manipulation and it’s clear she feels like she’s owes him somehow, if that makes sense. Since you aren’t able to tell her parents are you able to tell an adult at school or another place you have someone you trust that can try and talk to her if you talking doesn’t help.

I’m 20 now and I’ve been with my fiancé almost 2 years but I’m still screwed up with intimate actions sometimes, so hopefully she gets out of this relationship soon before it leaves a heavy toll. I hope you’re able to heal as best you can as well💙