Land cancel his j.HP and punish. It shoots you downward on block really fast, so you have plenty of time to punish him. Remember, hitboxes are spent once they're used, and he can't cancel into anything other than Blitzer from j.HP. The only time you can't punish him is if he does blitzer, in which case you can just PB it when he finishes. Alternatively, you can just jump block + call DP assist. If he doesn't have the chair and becomes sweep-happy, then just hold item drop and jump around. You can also sweep his sweep to trade, or win if you're close enough. Then, once he stops sweeping and goes back in the air, start zoning him like normal. His chairless sweep has 3 hits of armour, but he takes full damage from anything that touches it. Arm super loses if there are projectiles or anything in the way in front of peacock to block it. He will either get tagged by bombs or your assist will eat the hit. You can also just make yourself safe by watching for his PBGC and just noting your holes and waiting for him.