If he needs to use system restore,try from a command prompt in safemode.
Boot into safemode (tapping F8 on startup) and run the command
He will need to have admin credentials.
Surface Pro 5 News - release date, UK price, features, specs
Microsoft Surface Studio hands-on review: the iMac killer is here
Best Mac antivirus 2017
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.