Can someone enlighten me as to what is going on here?
Ha, you have a lot to learn about MEAF (Max Effort Abercrombie & Fitch) training. That's some hardcore shit right there! You need to do some high end flexion work so you can get the feel of heavier weight. That in turn will give you more confidence when going for a PR in the full curl.
Maybe he read one of those books that advocates heavy partials (power factor training) or heavy isometrics (max contraction training)......
More likely he is clueless in life.
I think I know that kid. No joke.
Maybe he's just into bone density training.