the batsman hits the ball with the bat and then we have two situation: A: the ball hits the non-striker and goes into boundary airborne. B: the ball hits the striker and goes into boundary airborne. What is this? Boundary six or four? Thanks!
In both cases this would be signaled as a six as the ball itself has not touched the ground. It is a similar situation to a fielder getting a hand to it on the boundary, but the ball still going over.
That said, if you've hit the non-striker and it's still gone for six, you may want to call an ambulance as well. ;)