What you should have in team to beat him:
Togekiss-Flame Plate[ADAMANT]Heat WaveSky AttackProtectAincent Power
If you can't find a Flame Plate then search UndergroundHeat Wave and Aincent Power are learned by a Move TutorProtect can be bought at the Veilstone Department Store
Hope this Helps!
Elite Four-Bertha:Coming Soon!