2000 cavalier clutch

Ok I am tryin to help my buddy out he has a 2000 cavalier 2.2 with a 5 speed. I have no clue what happened said the clutch is gone. I know he has a rear main seal leak. I can manually move the shift linkage and it sounds like it engages but still in neutral. Starts fine and runs good but no matter what i cant seem to get it in a gear. Is this a linkage problem or the clutch gone????