I would suggest waltzes and some nocturnes from Chopin, eg. Waltz Op.64, Nocturne in C# Posth. Pieces from Chopin are always enjoyable.
Practise, Practise and Practise. orPractise, Patience and Perfection
In that case, i heard of a nice rachmaninoff pianoconcerto or a 4th chopin ballade he could try :p