Honestly OP, I think you are overreacting. Unless there’s more going on that you are hiding from us you say that the reason you are worried your daughter will change faiths is because her boyfriends father converted from Catholicism to Orthodox. What he did is no indication of what your daughter will end up deciding to do. Also, the fact that you are worried her bf is gay just because he has some slight feminine mannerisms is clearly out there. Homosexuals can be very macho just like straight men can be feminine, there is no reason to go assuming such a thing about him based solely on the fact that he is not macho. I have a cousin who I can almost guarantee has is less macho/fits the ridiculous gay stereotype better than this man, but I can assure you he is certainly interested in women, not men. Unless there is more going on here that you haven’t told us I think that you are worrying needlessly. On top of that, there is the fact that your rejection of your daughters relationship, especially when compared with the love and acceptance she is being shown by her bf’s family will help lead her away from Catholicism and towards their faith. If you want her to stay Catholic then the absolute worst thing you could do right now is fight with her about her bf, especially if the concerns you bring up do not have a solid basis. Yes, you can still bring up concerns, but only in a loving and supportive way while still respecting the fact that ultimately, the decisions are up to her, whether she still lives in your house or not. Be loving and supporting, outdo the bf’s family in this, and you will have helped remove a possible obstacle to her remaining Catholic. However, if you continue to reject her bf and her relationship, and to argue about it with her or allow it to drive a wedge between you two you will be helping set up one more obstacle between her and the Catholic faith. If you are really worried about her converting, then start praying about how you can change to become more loving and supportive.