reject someone and still remain friends

Tweet

One of my girlfriends now is in a dilemma. She had a guy friend whom she got along very well with but while she has always treated the relationship between them as a purely platonic relationship, that guy expressed his love for her one day. She rejected him and now things are very awkward between the two of them. She feels bad for hurting him, and she doesn't want to lie to him either but she really does not want to lose such a good friend. Could she had handle the situation better? How can I help things between the two of them? (I do know both the guy and the girl) or is it better if I leave them to solve it on their own?