If all else fails, maybe getting reinstated might be just the thing to get him out the borg for good. I can tell you it worked for me.
Think about it. You get D'fd, suddenly your life is turned upside down and you have nothing and no-one. Especially if all your family and friends are Dubs. So there you are, all alone in the big bad world and you decide you can't hack it and want to go scurrying back to Dub World because even though deep down you know you were as miserable as hell while you were there, at this point it looks like a better proposition than staying all alone on the outside.
So you go back, you spend X amount of months kissing ass and being ignored at all the meetings, but you know that it will all be worth it in the end and after all, it was probably your own attitude that was to blame last time and thats why you were miserable, because really being in the Borg is the happiest place to be, right?
Then finally, after months of soul destroying grovelling, they let you back in and you get reinstated. Hurrah!!! Now you can get on with being happy and enjoying the fine association with your 'real friends' in the truth, not like those pesky worldlings who want to get you hooked on heroin at the first available opportunity.
So for a very short while you are the happiest person around. You commited the crime and did the time now you can start again with a clean slate and everything is wonderful. Until you realise that it wasn't your fault that you were so unhappy before. The Bro's and Sis's really are the most arrogant folk to walk the earth. You didn't imagine it. The elders are just as petty and full of their own self importance as they were before you were D'fd. And as for all the bull$hit they spout at the meetings, that was real too.
So soon enough you become disillusioned. All those months you spent suffering while you were trying to get reinstated, for what? The same old life as before. The one that made you miserable.
You've had a taste of the outside world and didn't like it, but that was because you were suddenly thrown out there, you didn't give it time and instead had the classic knee jerk reaction and went back to dubland. But there was potential in that 'big bad world', in fact alot more potential than in Dubland.
So you bide your time, plan carefully and eventually make you exit from Dubland. This time for good.