True, but you may be able to sucker your foe into trying to sunder YOUR (indestructible) weapon, in kind of an "Oh yeah, let's see how YOU like it!" type of thought.
This means 2 things: 1) he's not attacking you or anyone else for damage and 2) if he keeps trading sunder attempts, he WILL lose eventually.
This means 2 things: 1) he's not attacking you or anyone else for damage and 2) if he keeps trading sunder attempts, he WILL lose eventually.