[ The last thing she wants is to deal with another Emiya, that's why. It'd be too painful and he'd slip further out of her teachings--out of her reach. Painful to think about, especially when there's a promise tied to it. ]

He'd like to, but I could probably convince him that fighting in any manner is a bad idea. It'd only further aggravate the war.

You've heard of a neutral faction? Really?