Help please!!!?

this guy likes my best friend. I'm pretty sure she doesn't like him but she feels powerless to him. He is 17 years older than her. (she is 29, he is 46). i don't really like this person, i feel she is too good for him. she is much smarter than him and she still loves someone else. she just wants so badly to be loved and this other guy(the one she loves) has a girlfriend. she feels like this guy is her only chance i guess. he has children, the oldest is 17. i keep telling her she is too good for him, but she doesn't seem to listen. he comes over to our house and fixes things and he calls her all the time just to talk. It is so annoying because i dislike him and she just feels powerless. What should i do? Is there anything i can do?