Use of need in "He needed all the help he could get...)

Question

Peter needed all the help he could get from James and Sirius.

This construction seems odd. I usually hear "he got all the help he needed". But here it is opposite. What does it exactly mean? Is this construction common?

Answer 1

Peter could not do [whatever it was] without help. In fact, it was so difficult that he needed all the help that the others were able to give him.

It's quite a common expression.

Answer 2

Your second sentence, He got all the help he needed. describes what happened.

He needed all the help he could get. describes what he needed.

If he needed help, then what happened? Here are two possibilities:

1 He got all the help he needed.

2 He did not get all the help he needed.