Snake Shedding Behavior

My snake has been under his rock now for 12 days and hasn't come out at all. I lifted the rock to make sure that he was ok, and he seems to be, but he looks like he is about to shed, because his eyes are completely silver. My question is, should I take him out to feed him, (most articles say not to handle them when they are about to shed), and does it normally take this long? He hasn't tried to rub against anything yet and he hasn't even gotten any water. I put a shallow water bowl under a half tree so that he would be hidden and be able to soak but he hasn't gotten out of the rock. Should i be worried about him?