The mending spells wouldn't help with the walls, but it might find other problems to fix. It all lay in finding new ways to apply old spells. He did spend some time with them anyways, going over all the spells that everyone knew, and giving a few of his attack spell scrolls to the wizards so that they could copy them into their spell books, learning them. After that, he wandered about, helping where he could, though really just keeping an eye on the situation, though he could only use his awareness in his immediate vicinity, though he did cheat with fate to put him where he needed to be to learn the really important information *nudge*.