The best way that I know if is to have him do circuits, then make approaches at a certain altitude, say 50 feet. Then have him line up with the centerline and continue that and TELL HIM to go around, then do it again. Never lower than 50 or so feet. Then, once he is comfortable and lines up correctly, have him do it at, say 30 feet. Then continue that until he is again comfortable with that, then lower the altitude to 10 feet.... and continue this process until you don't tell him to go around at all, and he lands it.

The process is good if you TELL him to go around when it is unsatisfactory, and even if it IS. Continue to have him go around, and on approaches, you can continue to have him come in at lower and lower altitudes until you just don't say GO AROUND, and he then just goes in for a landing.

Then, once he HAS landed, a good landing, then you can have him do just about anything, but to follow the commands to go around or not say anything to him.

Also, during the landing sequence, do some dead-stick practice by having him go to altitude, first comfortable position so that he does not mess up the approach, then have him go to idle and make an approach. Once it looks good, have him throttle up and... you got it.. go around. After he is doing some fairly good approaches for dead-sticks, and after he has mastered the approach, then do some interesting dead-stick practice by having go to the downwind location, go to idle, then see how he handles the approach. Always remember that there are times that a downwind landing is necessary... especially if he does not have the air speed and altitude to get around for a good up-wind landing.

All this is part of learning to land, by the way.

This repeated activity may take a few tanks of fuel, but it works.

Good luck.

DS.