If you were the original owner of the pistol (you bought it new), it is still technically under warranty from S&W. If that's the case, you should call them and request a return label for a warranty repair.
Another option is to call Frank Smith. He will take care of it -
LSG, Mfg|Gun Parts|Warranty|Gunsmithing
It is definitely time for a gunsmith.
And don't give your brother any more guns - he obviously can't be trusted with them.