HOW LONG IS TO LONG FOR A QUARTER TO STAY INSIDE A 2 YEAR OLD?

My 2 yr old son has a sensory problem that causes him to put things in his mouth. So his latest trial run was with a quarter , that he swallowed. We took him to the Dr. and they did xrays.And sure enough theres the quarter in the very top of his stomach. Between his last 2 ribs. They said it would come out on its own. That was 3 full days ago. The quarter has moved less then ONE inch. (from new xray taken today) So they call a surgen who says its fine let him keep it in there for at least another 2 days. But because he is constipated (from xray looks like on both sides of the coin) puts him on a liquid diet untill Friday. Anyone KNOW the dangers of this? Do I need to take him to a diffrent Dr? Im lost. He doesnt seem to mind the quarter being there. But how long is too Long?