If he had Win8 or 8.1 with a UFEI bios, then key will be stored in bios.
This is what happened to my current very old mobo, 2013. I never get prompted for keys as it knows key already.
Like already said, try USB stick. Or look to the tool that patches win 11 to run on any machine.
Thats how I got windows 11 on my 2013 gaming setup. Ive even noticed an increase in general speed.
