Player down play continues!

[Loudwhistle]

BV game last night, during a rebound at visitors basket,visitor team member goes down on the floor during rebound and stays down in the Buddist praying position, (head almost touching floor, on knees, hands holding head) as home takes off down the floor on a fastbreak, he went down on the left side of the court and the rebound came to the home team on the right side, I stay with the down player while the game continues (3 man reffing) and the coach is chewing my arse to stop the play for an injured player. After about 5 seconds the player I'm shadowing stands up and we start walking down court where the ball is still being played, he's still holding his head with his hands over his face, just as we arrive at halfcourt he drops his hands and I see blood by his nose. (I look at play and the ball is out at the top of the key being passed around) I whistle play dead and then turn to his coach and say "coach he's bleeding" Player is subbed out. A question I have from this incident is 1. if I would have seen blood right away when the player was kneeling on the floor even though all the other players were at the opposite end of the court should I have stopped play immediately, or stopped play when I figured that the blood could "get" on another player? 2. Another question that I have is what if the player was totally knocked out? Do I stop play immediatley due to the fast break developing?