Say you find the asteroid on bottom of ocean. What sort of hoisting apparatus do you propose we use to bring it ashore?

Claw. Bucket. Reinforced net. Submersible ROV. Trained sea life. Anything that's not a magnet.

Supposedly it's in pieces from the impact. Small samples would be fine to locate and collect via ROV with a metal detector on it to check below the silt.

If they want mass extraction after that, then potentially a form a dredging could be used (vacuum and filter could work to leave the sand and silt on the bottom).

Core sample via remote controlled submarine. Magnets sounds goofy. I suspect he knows something we don't.

Arcade claw, with coin slot and all.

Too bad they scrapped the submarine lifting grapple equipped Glomar Explorer

https://en.wikipedia.org/wiki/Glomar_Explorer

Inflatable ballasts

Tractor beam.