Microsoft says if you decide to upgrade an unqualified system you will no longer have support from either them or Dell.  Right now the system may run fine, I have an older 7th Gen working.  But future updates/upgrades may start to cause problems for it.   The problem is we may not know for several months.  Would he want to take a chance on updating and 6 months later have to revert back to Win 10, for whatever reason might require it?
 APosting on behalf of my father regarding his 7773 2in1. It is not on Dell's list of laptops being supported for Window's 11 but it does meet the spec criteria using the Microsoft compatibility checker. So, the question is, what might the consequences of upgrading actually be? Does not being on the Dell list mean you cannot or should not upgrade? Has anyone upgraded a 7773?
Inspiron 7773 and Windows 11