Rights of a man in a live in relationship

One of my close friend was divorced in 2013 and has been living in with a divorced lady since 2003. They have no kids but the lady has been using his surname on all her documents lIke PAN Card, Adhaar Card etc. My friend is not working and his live in has been taking care of financial responsibilities through her job. Recently my friends lI've in started an illicit relation with another man and left my friend for one full year and stayed in a shared accomodation to enjoy company of another man. Aftet 1 year that othet PG was vacated by owner and she again went back to my frined but continues the illicit relationship with another man. One day my friend found some hotel bills of her staying in various hotels with that other man. That man is married. My friend confronted her with proofs but she behaved in a shameful manner and told that she is a divorced wOman and can sleep with whoever she wants. My friend has been living with her since 2003 till today. That lady has took my friends leftover cash about 1.50 lakh and given to her married lover other man. What are the rights of my friend in such a situation. Can he file a FIR for adultry by that lady and her married lover ? This lady is a bank loans defaulter and had low CIBIL ranking so did noy get loans whenever she applied. She with the help of a loan agent prepared another Pan CARD with a slighly different name and address and different fathers name and date of birth. she also created fake bank account statement and other neeDed papers to get a housing loan of 42 laks and has successfully got rhe loan on forged papaers with the connivance of the loan agent and the bank manager of a nationalised bank. My friend knows which bank and which branch has issued the loan and also has copies of her original and 2nd fake PAN CARDS. An office collegeue of that lady had sugggested her that loan agent. Please tell what action my friend should take now absolutely legally.