Helping to identify the winning hand

Was everyone's opinion of who should help identifying the winning hand in a home game? Last night, one guy goes all in, gets a caller, I'm not in the hand. To make a long story short, card on the river gave the caller, the chips are being pushed to him, when i notice it gave all in the inside card to a straight. I mention it, and all in is still in the game. I was thinking after though, that if someone can't even notice they have the winning hand, should someone else mention it? This isn't someone new to poker that doesn't know hands.