I argued against Butler before he was named DC. I find staying upset to be quite exhausting, so now that he’s the guy I am not going rehash whether he should or should not be the DC. He is, in fact, our DC.
I am going to assume that Snow and Butler can get along and work together well enough. If so, Snow’s presence should be a net positive for the defense and for Butler. If Butler needs some guidance, feedback or ideas, Snow can help him out. A former successful DC in the room has to help as long as they can avoid personality clashes and power trips.