You guys every thought that maybe it's not him, and it's the clutch system?

Stop flaming the kid about how he drives, he's done good for the last 110k miles did he not?

With that said, check for something called an internal leak on the cylinders. This is how you would check.

Have you foot on the brakes, and put it in neutral. Clutch into the highest gear you have, and keep your clutch depressed, don't wllow it to return. Let it sit there like that, and I bet within 10 seconds, your engine will stall. That's evidence of an internal leak in one of the cylinders. You won't notice this type of leak by looking at the fluid level.

Good luck.