I like his strategy better than yours. In general Baron > Poor House as payload here. Of course 5/2 makes it harder for you if you want to do that... I might have opened the way you dd as well with that. BoM is really good here because of so many situational cards (Baron, Shanty Town, Poor House) as targets. His Silvers should have been something else think, probably Wishing Wells. And he probably started greening too early. Nobles > Province on his turn 9 for sure.