JPJ: Your son needs an autotransformer (or step-up transformer)110vac to 220vac. It should rated at a minimum of 50va although I would suggest trying to get one rated at 100va which will run a bit cooler.
I have sometimes seen them on those racks offering travelling gadgets (you know, inflatable collars, secret money purses).
Two things to watch for - it needs to be rated at a minimum of 50va continuous (if the rating is 50va intermittent it may not last long). Also, be aware that there are "step-down" gadgets from 220v to 110v (basically a power resistor in a box). These do NOT work as step up devices - you need a transformer. Alternative source of supply would be a radio/electronics parts supplier, although then you might get a bare transformer and need to put it in some sort of a box.
Hope that helps ..
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Feline
(I Sit, I Watch, I Smile)