Subbing Player on a IW

[JPaco54]

Sub waiting to come into the game to replace the foul shooter. Foul Shooter misses shot, defense rebounds starts to dribble, horn sounds, players continue for a second then Ref blows his whistle, for what reason we do not know. Play stops, points to partner who is Trail to inbound the ball, a fan yells to the ref there is a sub and he tells the fan the player can wait. Fan yells back, now that he has the ref's ear, but you whistled the play dead and you can sub on a dead ball. Ref says to the fan, he will wait there all night if I want him too.

I thought the sub could enter at this point even though the Ref had an IW. Can not the sub be beckoned into the game at this point?

I also had a problem with this ref talking to the fan at a BV HS game. Classless...