Just to correct you slightly, The order of things will be:
PPL
Night Rating
ATPL Theory Exams
Hour Building
CPL
ME Rating
ME IR Rating
MCC
In the UK the modular route will cost around £50k and the integrated will be around £85k, approximately anyway. You don't need to do an IMC rating. Also if he is serious about doing this as a career get him down to the CAA at Gatwick to do a Class 1 medical. Without this medical he cannot be a professional pilot.