Swing feel is not triplets! It's approximately a triplet but if you play it in strict triplets then it sounds almost as bad as playing it square (as eighths). Swing feel is a feel and all the members of the band have to agree on where that swung note is going to hit. What is happening is that the drummer is not locking with the rest of the band. Maybe he's playing square but he's definitely not listening to the rest of the band.

So what I would do is put on a jazz recording that has the swing feel you like and then have the drummer play along with the swing of the drummer in that recording. If he can't do that then he's hopeless until he develops an ear. Send him home with the recording and tell him to play "like that".

If he can play along, then first play the recording with him playing along, then you start playing along and then finally you continue to play without the recording.

Swing feel is not triplets! It's approximately a triplet but unless you're Elvin Jones, if you play it in strict triplets then it sounds almost as bad as playing it square (as eighths).

Paul Berliner in "Thinking in Jazz" writes:

Within the realm of beat subdivision, myriad nuances of phrasing in between an even eighth-note subdivision feel, a dotted-eighth and sixteenth-note feel, and a triplet eighth-note feel are associated with the dynamism of swing.

Swing feel is a feel and all the members of the band have to agree on where that swung note is going to hit. What is happening is that the drummer is not locking with the rest of the band. Maybe he's playing square but he's definitely not listening to the rest of the band.

So what I would do is put on a jazz recording that has the swing feel you like and then have the drummer play along with the swing of the drummer in that recording. If he can't do that then he's hopeless until he develops an ear. Send him home with the recording and tell him to play "like that".

If he can play along, then first play the recording with him playing along, then you start playing along and then finally you continue to play without the recording.