If it's a new gun, have him check the striker - mine came FULL of thick, gritty grease; didn't cause any problems in mine, but may be worth a look - check the "sticky" on this forum under "semi-auto" section; good description of how to remove and clean the striker.
Well, I'm afraid this should be yet another SR9 that will take advantage of Ruger's great customer service; better give them a call - they probably will sed a free shipping label and reccomend sending it to them for repair/replacement. Might want to check with the store he bought it from also - maybe they can make it right.