His forehand looks kind of "strange" because he uses a different take-back than most ATP players. It reminds me of Roddick's forehand take-back a couple years ago, when he used to be good. Both of them use the elbow extensively to bring the racquet back.
It's a semi western on most of his rally shots, but he appears to shift it to something between semi western and eastern on certain shots, such as when returning.
On that note he has some of the quirkiest takebacks on both of his groundies in the entire tour.