I hope Sean does play it, and all the way through too. It's not scary in the way that Amnesia: The Dark Descent was, it's more disturbing and thought provoking (although there are a couple of instances where Sean will have his nerves rattled). It's a smart game, Sean should like it if he can keep his fear in check.
However, in his Hearthstone stream yesterday (October 14th) he mentioned that he'll be playing Overwatch for a few days at the end of the month (the Beta is released on October 27th) so I fear that a Soma playthrough won't happen.
I hope that I'm wrong.