Buying him back in

[Adam]

Back to the injury thing again. 10th boys last night, and V41 gets injured in the eye on a foul by H32. After I call the coach on the floor and he gets attended to by the trainer, V41 looks like he can continue. I inform the coach that if he wants his player to stay in the game, he will have to use a timeout.
He agrees to use the TO, and I inform the bench and all the players start heading to their benches.

After a couple seconds of yapping by the assistants, the head coach asks me if he can just sub for the player. I tell him, "sure, but you're still using the timeout."

He wanted to keep the TO, because his team was down and mounting a comeback.
Was I correct to not let him change his mind at that point?

Adam