You did well to get 80GB back in all honesty, hope your friend learns from this.
If it were one of my own computers I would say yes but those owned by others I would always air on the side of caution and reinstall Windows 10 and then upgrade to Windows 11, couple of reasons why I would go that route here, we know nothing about the rest of the PCs hardware as in if it meets the minimum system requirements for running Windows 11 and we do not know if the Windows product key is OEM or full retail, it is far easier to deal with any activation problems if you have a retail key as opposed to a system builder/ an OEM key linked to a Dell, HP or Lenovo etc machine.
If I were intending on the direct to Windows 11 I would have all the required Windows 11 drivers saved on a flashdrive + the present Windows 10 product key written down and sat in front of me, the latter in case the key got asked for along the way.