I think that Silas, despite being a former member of the Council, wanted there to be some sort of peace between the Elves and rest of Alledian's.
Trellis states in the first book that the whole war might have been part of his mess, that he may have failed at bringing peace and made things worse or something. And somewhere there was a discussion about the council letting the Elf King live and try and cure him of his curse. Maybe his idea? And what about the book that Virgil has in Trellis' memories, the one titled "On Stone Power", maybe it was a gift from Silas?
I dunno, maybe I'm hoping too much and maybe Virgil just had the same ideals or thought it was interesting, but it is a small possibility, right?