it would seem he didn't read the instructions fully and closed all services, he is meant to have not closed windows services. Just everything else.
On another PC, download the
Windows 10 media creation tool and use it to make a win 10 installer on USB
boot from installer, on 2nd screen after languages, choose repair this pc, not install
choose troubleshoot
choose advanced
choose start up options
hit the restart button
choose a safe mode (it doesn't matter which) by using number associated with it.
Pc will restart and load safe mode
once he gets to safe mode, right click start
choose run...
type msconfig
set windows to normal start & restart PC
another choice is to run system restore and see if he has a date recent enough to roll back too
boot from installer, on 2nd screen after languages, choose repair this pc, not install
choose troubleshoot
choose advanced
choose system restore