He is probably starting each note with the air "Hoo" "Hoo" "Hoo" or stopping and starting the tone in the throat with "Guh" "Guh" "Guh" or a variation of one or the other. 
My suggestion:
-Have him say tu tu tu tu tu without the sax.
-Then tell him to take a big breath and hiss a real long hiss.
-Then have him do the same but break it up into short hisses like "Tst" "Tst" "Tst" "Tst".
-Then have him imitate a "rainbird sprinkler" with fast spurts of air, then slow, then fast again. This reinforces the tongue acting as a valve (and using pressurized air).
-Then have him put his thumb in the mouth pretending it is the sax mouthpiece pressing the top teeth into the thumb print part and pretending the thumbnail is the reed.
-Then, letting air leak out the sides so you can hear it, have him do the "Tst" "Tst" "Tst" sound again but this time touching the thumb nail with the front of the tongue instead of the top teeth.
-Next using the neck and mouthpiece only have him say "Tu" "Tu" "Tu" "Tu", then blow the air and spit 4 (imaginary) spit wads off the tip of his tongue "Ptu" "Ptu" "Ptu" "Ptu" then do the same into the neck and mouthpiece "blowing his tongue off the reed".
-Watch for excessive movement in the throat or chewing with the jaw. Help him to keep the chin still and move just the front of the tongue a short distance.
-When the neck and mouthpiece (small sax) sounds good, go on to the full instrument and do the tonguing exercise on an easy note like B natural at first.
-If he has difficulty with any one of these steps, go back a step and repeat that one a few times. In between practice times on the sax, encourage him to walk around saying "tu" "tu" "tu" or spitting imaginary spitwads to reinforce the tongue (and air) movement.
Be patient! If he has been allowed to play an entire year "tonguing" incorrectly, that poor habit has become very ingrained and it will take time and practice to extinguish the poor habit and replace it with the proper one. Good luck. Hope this helps. If you have any questions send me an e-mail or a private message and I will be happy to communicate further.
John
My suggestion:
-Have him say tu tu tu tu tu without the sax.
-Then tell him to take a big breath and hiss a real long hiss.
-Then have him do the same but break it up into short hisses like "Tst" "Tst" "Tst" "Tst".
-Then have him imitate a "rainbird sprinkler" with fast spurts of air, then slow, then fast again. This reinforces the tongue acting as a valve (and using pressurized air).
-Then have him put his thumb in the mouth pretending it is the sax mouthpiece pressing the top teeth into the thumb print part and pretending the thumbnail is the reed.
-Then, letting air leak out the sides so you can hear it, have him do the "Tst" "Tst" "Tst" sound again but this time touching the thumb nail with the front of the tongue instead of the top teeth.
-Next using the neck and mouthpiece only have him say "Tu" "Tu" "Tu" "Tu", then blow the air and spit 4 (imaginary) spit wads off the tip of his tongue "Ptu" "Ptu" "Ptu" "Ptu" then do the same into the neck and mouthpiece "blowing his tongue off the reed".
-Watch for excessive movement in the throat or chewing with the jaw. Help him to keep the chin still and move just the front of the tongue a short distance.
-When the neck and mouthpiece (small sax) sounds good, go on to the full instrument and do the tonguing exercise on an easy note like B natural at first.
-If he has difficulty with any one of these steps, go back a step and repeat that one a few times. In between practice times on the sax, encourage him to walk around saying "tu" "tu" "tu" or spitting imaginary spitwads to reinforce the tongue (and air) movement.
Be patient! If he has been allowed to play an entire year "tonguing" incorrectly, that poor habit has become very ingrained and it will take time and practice to extinguish the poor habit and replace it with the proper one. Good luck. Hope this helps. If you have any questions send me an e-mail or a private message and I will be happy to communicate further.
John
