As far as I am aware most laptop chargers will accept from 100 to 240v. To check you should look on your charger and it should state the input voltage that it will accept. He will of course need to have an adaptor as the UK plug will not fit USA sockets.
I have used my laptop on USA power with no problems.
I take it that he wants to get on the internet. Many hotels provide free wifi or internet access but they may charge and he needs to be careful about security.
If he has not taken a laptop through an airport before then it needs to go through security out of its bag separately.