Ummmmmmm......don't do that. That player has autoresigned he can't play the game anymore, he's out. Take his stuff don't make him stronger.
If by "keep the wall stronger" you mean you want to use his outposts as a buffer from enemies you can do that, but I'd just take the bases if I were you. You can have an attack land right after the enemies attack to take the base after your opponent has wasted a bunch of drillers taking it.
My faith has found a resting place,
Not in device or creed;
I trust the ever-living One,
His wounds for me shall plead.
I need no other argument,
I need no other plea,
It is enough that Jesus died,
And that He died for me.