Love is not wicked, is the people that are involves that makes it wicked. The young man in question should help the sister out because is not easy paying all the bills alone.

I agreed with you on the advice you gave her. She should do what will give her peace of mind that is all. If the guy is not willing to cooperate, he should find himself his own apartment so that he can do as he pleases because he is not a child any longer.