Quote Originally Posted by Pells View Post
If he's using a mouse, then he has a keyboard. Targeting other players (in a four man dungeon) is keybound to F2, F3, and F4 by default. Broken mouse button doesn't explain this.
Maybe he uses mouse-over healing. Getting tired of people always coming back with an excuse of why something can't be a valid excuse. Not everyone plays this game in the exact same manner as you.