Believe Elliott is Aaron Donald's nephew, not brother, but it seems like they have a pretty close relationship.
Either way, seems like Pitt is the way this had been trending for a while, which makes sense for all of the obvious reasons - hard to go somewhere else when your uncle gave $1M+ to the football program of the hometown school. Playing in front of 30k obviously didn't hurt Aaron, and it looks like it won't hurt their current DT Twyman, either. It is what it is. Gilliam looks like a heck of a DT prospect in his own right, and it'd be great to get good news from him.