Oh the poor thing! I've heard some stones can be left, did they scan him when he had his gallbladder out? My surgeon (had mine out Friday) said he doesn't do it routinely unless he thinks it's needed.
Not sure if he did with mine as he said it had a split in it and some stones had come out (and I assume maybe bile as I was looking decidedly yellow!) but he had got them all in a bag (would have questioned more but had just woken up back in ward after a big morphine dose in recovery).
He said if there are any floating about then they can do an ERCP (?) where they can go in down your throat and pick them out - guess it depends what's where though.
Have they tested enzymes and such (amylase?), they did that to me when mine got infected as thought with the pain it could have been pancreatitis (thankfully not).
I hope they sort it for him soon and can at least get the pain under control x