If you're looking for a solid vgc team, you can always check out tournament reports
that proclaim at least decent success if you just want your friend to have a team able to compete. If you'd like to make the team yourself, I'd recommend getting veteran help. You can hop onto #Pokemon
for some vague advice or enroll in the next round of VGC Battling 101
on September 27th for a more thorough 1 on 1 learning experience.