I put this same situation up on another league and this was one response I was given which I think was correct.............I won't post the persons name......
That should never be able to happen in a fantasy league . If it would not happen in a real NHL,NFL,MLB ,etc. then it shouldn't be allowed to happen .The commisioner or governing body of the league is responsible to make sure it is taken care of properly. In the league I was in for MLB if the team owner choice to quit the team stayed intact as is for remainder of the season or was sold (buy in) to a new owner. We always had guys who wanted in our league so it was no problem finding an owner. If I was in your postion I think I would be upset,Let us know the outcome.