A1 must be replaced before any request for a timeout can be granted to either team (NFHS and NCAA).
Here is how I would have handled it:
1) Inform Coach A that A1 has five fouls.
2) Instruct the Timer to start a thirty second count.
3) Inform partner that A1 has five fouls.
4) If Coach A has not replaced A1 and is still requesting a timeout, politely remind him that he has to replace A1 before any request for a timeout can be granted.
5) After A1 has been replaced, grant Coach A's request for a timeout.
I think that is the best way to handle the situation, because it follows the protocol for reporting fouls, replacing disqualified/injured players, and granting a timeout, as described in the NFHS and CAA mechnics manuals.