Minisforum V3 is 12” and less than 1kg.
But it is not quite a laptop, expensive and very powerful - not sure if that suits you.
Linux wise, most of the stuff works (sleep, power profiles, volume buttons, fingerprint reader, face recognition, pen, touchscreen). Things that don’t work are automatic rotate/accelerometer.
I’m super happy with it, running arch, doing development and using VMs.
Depends on their specific needs, so they should probably jump into some Linux community and ask for themselves.
My anecdotal evidence includes vastly different experiences.
I have a friend who hates Linux desktop and exclusively uses it for running dev related stuff via WSL.
Another who uses Linux desktop primarely, but dualboots Windows for certain games.
And I am on Linux single boot and rarely use KVM (without GPU) for running my CNC or other software.