What to do to save it? A relationship that is as good as down the drain?? Are you a magician or something? Try turning back the hand of the clock lol
you said, he said and i quote "the girl is nothing to him anymore and that if he continues with the relationship, he'll never love her" . . and you want to save it, lol you're the funniest one today

Ok first of all, what caused the sudden change of feelings? If its something the girl has done, then it might only might be reversed. But if your friend really said it the way you expressed here then the best advice you can give your friend is to let the damsel walk

between why is he still holding unto her, when he for sure knows he's just wasting his time and hers?? He knows its literally over,and he's still there wastin her energy and love?? Seems your friend is selfish too

He should try and break it dowm to her as softly as possible, its always painful and devastating, more for the party that didn't see it coming, but at the end of the day its the only solution and the sooner he did it and got it over with, the better for them

The longer it took, the more pains he'll be endangering her to, and its not cool!!!!!!