Hello. I want to share with you a case and ask your opinion.
A member of my family, adult male, a young person, is in a relationship with a possessive woman much younger than him. Before this relationship, he was very happy, communicative and jovial person having lot of friends, going out frequently for drink with his brother and friends. But since he started this relationship, his mood has changed and worsened, being now with family reserved, stiff, dark mood, with little communication with his family, being her now his only world. She is very possessive and has isolated him from almost all his old relations of friendship and in the past, the only moments he dared going out with someone from his old group, she argued all the time until he didn´t do it anymore. He now hates his brother, because the brother has criticized the possessivenes of the woman, his money expenses although they had always a good and close relation, and his old group of friends is abandoned.

Do you think ths relationship is usual, normal and acceptable and thats the way such things go, or it seems a toxic relationship? Do you think this person needs any advice, or should be left as is?

Thank you