Personally I think your trainee doesn't really have as much opportunity to get good as some you could find on the transfer market for relatively low cost. But if you really want to train him, here's my thinking...
-train passing until he's at average/respectable passing. It's an invaluable skill for any position.
-train pressure until OD is up to inept. It's not exactly high, but it takes a lot longer, and with the player you've got, he's never becoming a true superstar.
-train one-on-one for forwards until driving is at least average. It should get his handling to around prominent and inside shot to prominent/prolific, but if not, don't worry.
-alternate ID/Rebounding until around sensational/sensational, maybe even tremendous/sensational.
-inside shot to sensational. If you really like shot blocking, up to proficient, but the skill isn't nearly as important.
Other than that, I'm not really sure. That should take a while, and take him close to the end of the days where it'd be worth training him.