You can remove his name from the Welcome Screen, while still maintaining the user account.
Start the Registry Editor
Go to HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ Winlogon \ SpecialAccounts \ UserList \
Right-click an empty space in the right pane and select New > DWORD Value
Name the new value exactly as the Username
Leave the Value data as 0
If you want to enable this user again on the Welcome Screen, either double-click the Username value, and change the Value data to 1, or delete the Username
Close the registry editor