[CentOS] Desktop for newbies

Folks

I'm about to set up a non-root user on a Centos=7 server that I 
control for a friend.  It is in his home, so access is local.  He's a 
refugee from the latest Windows 10 Upgrade.  I'd like a suggestion as 
to which of the several possible graphical desktops to suggest to him 
and set up for him as his default.

My aim is:
- Allow him to try out Linux as an end-user
- Let him start to feel comfortable with the desktop
- Learn the new idioms for familiar programs and functions

And later
- Give him his own system with root privileges.

Suggestions?

David