Delay of game warning

[feeli99]

A1 was fouled by B1. As A1 is going to the foul line to shoot, the table informs the ref B1 has 5 fouls. Ref signals coach of B1 to sub for B1. Coach yells" I have 30 sec.to sub". The trail ref lines the players up to shoot 2 FT's. After 30 sec. the lead ref informs the trail to administer the first FT. The coach is informed he is delaying the game. He screams I can't allow A1 to shoot because he hasn't made his sub yet. After the first FT the sub enters the game. Was I right? and if he had missed the FT could I have allowed him to shoot again because of the delay of game warning given to the coach?