You can give him a soak for a half hour or so in a little tepid water, (just off cool) and just enough water to cover his sides (don't make him have to swim and keep an eye on him while he is in there). Then after the soak, gently rub the edge of the unshed area, work in the direction of the head to the tail, the natural shed direction.
Don't pick at it, just rub gently. It should start to lift and roll off like peeling sunburn. If it doesn't lift and roll off easily, soak for another half an hour and try again. Once it starts happening, it is a gentle process.
