My friend is stuck at the airport in Amsterdam on his way to Australia he has paid his fare but will lose this if he can't find the 820 needed for the BTA .Does he need BTA to travel from Amsterdam to Australia?

Scam, Scam, Scam.
There is no BTA.
Your friend is not in Amsterdam.
Your friend is not your friend.
I don't think you go through Amsterdam to get to Australia from anywhere.
Scam, scam,scam

Well known scam.

If you got it supposedly from someone you know, then all it means is that the address is spoofed or their account was hacked. If you really do know this person, call them and you will see they are not in this situation.