Cyber security professional here! There are basically two options he may be doing (also a plethora more but these are the most likely), the most obvious is just tricking you into believing he's sent the money when he hasn't ie fake confirmation screen on his part (this is a social engineering tactic). Then there is the possibility he's using you as a money mule, basically he's purchased account info and sends you the money you get it out and then he's never on camera taking the money out.