I deleted my user to free up space/storage but it showing the files still there, help!

HI, My son mac book pro got filled up quickly with movies/photos and other, he is a photographer. We backed up his computer yesterday and then went into user accounts, and he is the admin and we deleted this user, thinking it would clear up space, but it didnt. Does anyone know how to access these files and then delete them? Thanks! Pam