I only drive with antilock brakes these days, so I concede I may be out of practice with pumping them.

I believe the discussion began with the point that what was specified was a need, not a favour. I was addressing the inaccurate suggestion that the passenger in question NEEDED to close the bins. As the OP indicated, the FA said to the OP's son:

"I need you to get up and close the overhead bin."

and with that information from the OP in mind, I countered that given that bin closure is not addressed in the safety video, which does indeed cover what passengers NEED to do, the statement (not a request, note!) given by the FA was inaccurate.

As I made my replies, I was also thinking of the comments earlier in the thread about how the FA could have phrased the question as just that, a request for optional assistance, and not a petulant sounding demand. Example:

"We would like help closing the bins and would be most grateful if anyone in the aisle seats could close any nearby bins" makes it clear they are asking, not demanding, and I in turn would be reassured that I am only being expected to assist, not take on final responsibility. (Even if pax close the bins, the crew still needs - speaking of need - to check that they actually were closed.)