there are some pretty grim places in london,don't go anywhere near peckham

to be honest its better to stay outside london and just travel in by train
windsor is a real nice place to stay
places like barnes bridge and kew are pretty nice if he wants to be in london
chelsea/fulham area is good as well
there is a hotel at chelsea football club

which is real nice and a good base to travel from and he can see some REAL football as well
best bet is find out what he wants to visit and i can tell you if its crap or not