Ty Berry missed so much of the season that his total +/- is meaningless. Maybe if they ranked the players based on per-game +/- instead of total, but he still missed so much of the season that this doesn't tell us anything. He was playing his best ball of the season and was a key contributor when he was injured.
+/- just doesn’t translate well in bball. The best player on any poor team will almost always have the worst +/- simply because he played the most minutes.