We are flying out of LAX next week on Lufthansa Airlines to Dusseldorf. Our carry-on meets the size limits, but are limited to 8KG. My wife's bag weighs 20 pounds. Do they really check the weight?
They can, and often do.
Wear the jacket and stuff some things in the pockets if you can't shift weight around between the two of you.
8 kg is 17.6#, so you are only 2.4# over. You don't need everything. Leave out some things, move others around.
It was several years ago but LH weighed my carryon bag before a trip from the US to Europe.
If the items are absolutely, fundamentally imperative for you to have on board, just do what I do: fill up your jacket pockets. Otherwise... leave 'em/stow 'em.
I think it is very dependent on the check-in staff. On several occasions with Lufthansa nothing was said or done with carryon luggage. However, on two occasions the counter personal with death on size. Forcing every carry on bag into the sizing box and it was a half-inch to big it was checked. Which meant that every wheeled carryon size bag was been checked. But no weighing of bags. On the other hand, United has given me more grief over weight than any other airline. It just depends.