The only way is to infect his pc with a RAT.
There are plenty of free RAT services out there.Tho making a RAT undetectable from antiviruses will costs you some penny's. ( You will need a crypter which most of the times costs some money )
With RAT you can delete or take files or even control the whole mashine. ( Broswing drivers , webcams , screen etc )
Most known free RAT is DarkComet. You can search on youtube for videos on how to set up it and videos making fun of it with idiot slaves.