Is there a way to gift credits to another WGT player?
Only indirectly:
Send him a fiver by mail, or the number of a gift card by email so that he can buy credits.
Subway gift cards are easy to get and quite handy for this. The sneaky part is you have to part with actual cash, not credits accumulated. Really throws multis a curveball. :-)
You can play a challenge for credits .. Let the person win and they get the credits .
However they will have to have the credits to wager first ..
Create a blitz round in challenge mode, invite him, set the desired amount and then forfeit the round on the 1st tee ;-) The cheapest way to do it and most people have done it this way for ages.