The situation sounds like a college friend of mine who "somehow" always "had the bad luck" to fall in love with gay
men. Time after time after time. It didn't take me long to realize that a guy's attractiveness was inversely proportional to his availability. Being attracted to the unobtainable takes away all responsibility for one's own love life and happiness or for any need for self-improvement.
My personal g.a.ydar is completely busted half the time, always when I find the guy interesting, I even had a crush on someone who hadn't come out to himself yet (so I now joke that I 'break' men and turn them g.a.y) - but in the same time I can rationalize why I am attracted to certain guys that I know would not be a good idea to date.
I was keeping myself from being happy with someone because I didn't have the self confidence to think "hey! I deserve to be happy, bring me the cute* guy for once".
I found someone who boosted my confidence and I know I act and look "better" and happier and I'm probably more attractive to other guys.
What I wanted to say is, I didn't need therapy to come to this conclusion, because I did the work on myself to try an analyze what was going on, but OP's friend could use it, I just don't know if there's a good way to broach the subject...
* I have a very large spectrum of what cute means, and it's not just the looks - I'm not looking for a supermodel since I know I'm not one, and I believe look is not all there is in someone.