its up to you, i have save dozens of relationships by
reassureing them their relationship still has a chance, and both
parties still care for each other and the main point of the qurrel
was coz they did care for each other.
Anyway pretty hard for the guy, unless he is willing to humble
himself and apploguise to the girl... and win her trust back. don't
think its gonna be easy.
Well... personally, i think u care for both of them, and if u feel
they are better off juz as friends, then so be it. its a decision
for you to make, not for anyone of us to. 
well, as the saying goes, strike when the iron is hot.
