you're still my gf right babe...?

My brother (owner of this account) is an Among Us porn addict. He apparently started "ironically" watching Among Us porn and then it started to seriously turn him on. Once he accidentally sent Among Us anal porn to our family group chat and my mother got angry and we started discussing it as a family. My sister was probably the most disgusted one and wants my brother to get a therapy because she thinks he has an addiction and it is dangerous for him. I say that he is just discovering his sexual self, and masturbating to Among Us impostor being anally penetrated by another Among Us impostor is not wrong. My brother is really embarrassed and just wants all of this to end. I don't think that my parents really care that much and it's just my sister still talking about it. What should I do to convince her that Among Us hardcore porn is OK?