Right forget about the insurance not being valid for a moment, when it was cancelled, what he should have done etc etc (which will not only cost you in points, a fine, court fees and the repair bill for his car). If you have a copy of your bank statement showing it going out so you thought it was paid, plus a copy of the letters from the insurance plus when they arrived you might be able to get the number of points reduced by turning up in court, pleading your case and pointing out how you need to drive to be able to work etc etc. Just make sure you are totally honest with them