Weโre not talking about hurting doffy... you said Kinemon can hurt BOUNDMAN. the barrier ryou kin knows is effective against kaido specifically. Kinemon nor zoro knows internal destruction haki.
Also please explain how killer can hurt kaido but somehow doffy canโt?
When has killer shown ryou?
Yes he can. If Kinemon can hurt Kaido, whose durability feats are > Boundman, then it's only reasonable to say he can hurt Boundman too. And no, it's not effective only against Kaido, AdCoA ignores durability.
Killer has sound-based attacks through sonic shockwaves, that's how he hurts Kaido. What attack Doflamingo has to actually wound Kaido if he failed to hurt DR Boundman?