The best thing you can do is be SUPPORTIVE of your friend. Whether you like the girl or not, be supportive. If you feel a certain way about her and feel like you need to tell him, do so, but let your friend know you got his back no matter what. I speak from experience, a great deal of experience, that bros before hoes is a motto to live by. When things fall through w/ that chick, if you were a dick you are out one best friend...that may be something you regret for life.