I stand to be corrected, but I think that as long as he gets the Seminar Certificate it might be possible to have the passport sticker/stamp at NAIA airport.
Please give them a phone call on 879-8565 to check.
The desk is open from 5am to 12 midnight every day.
When you've called can you inform us the result?
He will not be allowed to leave without the proper documentation (CFO sticker/stamp)