If he's a true jerk, he'll report the now cancelled debt to his country's equivalent of the IRS. If you owe money and some or all of that is cancelled, in many countries the amount cancelled might count as income to you for tax purposes.

I'd expect that in this case it would not be income, because it sounds like the court determined that the debt was not valid in the first place and so it is more of a "there was never a debt in the first place" than a "cancelled debt" situation, but being investigated to determine that would likely be annoying.