Julius: Cura, Cura, Balloonga x6
But even with Balloonga, the fight is no cake walk. If you were on Standard like me, he would stumbles every two Balloongas, but you still have to dodge him and stay away from those punches.
When he summons lightning, you better stand there and guard so it doesn't hit you. Also, whenever he jumps onto the building and body slams the ground, start flowmotioning like crazy off the walls immediately. Travel the whole area until his electricity is gone because a simple bunch can neutralize a command which can be very annoying and deadly. As a side note, I wouldn't rely on flowmotioning off the poles because those are easily broken.
As for everything else, just Balloonga him when you have the time, dodge his attacks, and heal before it's too late.