A guy friend of mine likes a girl.?

she is already in relationship with another guy from last 2 years, my friend is a really good guy and a true blue gentleman, he met this gal exactly 2 years ago and just after their meeting the gal was taken, when my friend met this gal he fall for her but at that time he was preparing for the indian army to be an officer but his hard work went futile and right now nothing is good in his life, a totally screwed career, etc etc, he says that he is totally ok even if the gal says no to him b/c he is expecting it he just want to let her know that he likes her for that he sent her 2 mails but the gal is not responding so my question is that should he go to her and take her rejection and move on or he should not tell her his feelings and get burnt from inside for always ?