A US keyboard will not a £ sign. There is a combination of keys to get one, but this will have to be used when she gets back.
The three pin 'cloverleaf' power socket is more common in the US than the figure of 8 lead. So I would ensure the UK laptop uses one, so only the power lead needs changing.
My power adapter can recognise any voltage from 100 to 260, and 50 or 60 Hz.
Ken