I think they all need a pairing cable as you would expect. That friend of yours needs a different wife.
I would open up the wall and run the lead in the wall if that is a deal breaker.
Actually the solution to the interior design issues is a building project. We have not had wires showing in our homes.
This is a system we had in our Grand Forks home.
You never saw wires and when you shut the door, the equipment was not seen.
No speaker wires visible either.
There is absolutely no need to have a wire visible, if you are smart about it.
You don't have to go wireless not to have visible wiring.
There is nowhere enough good interior design around audio and AV systems. Opening walls is actually not that big a deal. Drywalling is not prohibitively expensive and repainting is easy.
If your friend commits to a bit of remodelling he will get a much better, more versatile and actually more enjoyable and livable spaces.
My wife would not tolerate wires seen about the place and I would not expect her to.
Even back in 1953 when we moved into the OP we had no visible wires. When doors and lids were closed you would have had no idea there was an audio system in the room. So I have over 70 years experience with "wireless" systems, at least non visible wires.
In my late teens I got the job of installing an audio system in the Guilt Hall of the former Earls of Darnley's historic home. That had an organ in the Balcony that had been played by George Frederic Handel. I leaned an early lesson on that job, as it failed fairly promptly as mice ate through the wiring I had passed under the floors.
Lesson learned. Wires go in conduits!
