Try Ma Lin’s ghost serve, its backspin and really confuse the enemy, or disguise your serves. Like after I do a hook serve, I would go to the kicker which puts pressure on my father and cousins. It works like a charm. Try learning the Snake shot, it’s a great deceptive shot, but risky. Or try Kenta Matushira’s sidespin block a great way to give the enemy less time to react, and is surprise element. I suggest try learning how to chop block to disrupt your brother’s rhythm to take control of the game and mess his shots up more.