So my 12 year old daughter is meeting her father at the boarding gate... he says that only I am allowed to go with her but Is it true I can only get one temporary pass?

Both parents can accompany a minor to the boarding gate or meet a minor you work this out with the airline for the passes

I'm guessing only ticketed passengers can go through the security checkpoint. The airport staff wood accompany her to the gate.

I would call the airport.

Is there a limit to the passes I can get?