That would be a great idea but there is one problem, for some reason I can't figure out he now says that he wants to also be able to use a softphone on his desktop computer, and I don't know of any way to set up a VPN so that ONLY the traffic from the softphone would flow through it. Also, I don't know much about VPN's and he knows even less than I do, and I would not trust that he could set up a VPN that would only allow traffic from his softphone and not all his web searches and other traffic. And he is geographically too far away to go set it up for him, but even if I could he's the type that would monkey with it and change the settings after I left.
I had actually read somewhere that it is possible to use an Obihai phone with OpenVPN and I had given some thought about maybe trying to set it up just for the phone, until he informed me that he also really wants the softphone to work. Anyway, I'll have to give some more thought to all of this but at this point my enthusiasm for trying to make it work is considerably dampened.