Add another Animation to the button you want to break. Create a couple frames with each one shattering pieces off in all directions. Call the animation Break or whatever you desire.
In Event Sheet, create an Event that when your character plays an attack animation and then Add another condition where player collides with button: Now Add the Action. Set Button Animation to Break (or whatever you named it. I’d also add another action that uses System-Wait-0.25 (setting the time). Then add 3rd action-Button-Destroy (so it can no longer be affected by player or until you reset it.)