Hi,

I have never been in a situation like this but when I wanted my ex to leave the house my mother threatened to move up there and stay in the spare bedroom... Really would have put a crimp in his freedom I think. It didn't come to that and he did move out on the requested date.
Cutting of the elect. may work but I think that speaking with his parents is probably the way to go - chances are they know nothing about what is going on.
Good Luck with it all and let me know how it goes.