help

  1. He offered his help on unloading.
    1a. He offered his help for unloading.
    1b. He offered his help in unloading.
  2. He gave me a help with the housework.
    2a. He gave me an assist with the housework.
    Please correct all.
    Thanks.

1b is correct.
Alternatively:
He offered help to unload.

2, He gave me help with the homework.
2a He gave me assistance with the homework.

I actually came across this very example here thefreedictionary.com/assist and I’m baffled by it. Is it possible that this is AmE usage?

“He offered his help with the unloading.” Can this be used instead?

Thanks!

Possible, but I suspect it’s far more likely that it’s a typo or other error.

Yes, indeed. It’s far more preferable.