No question that he messed up. No penalty turn would save him or we would all zoom over at the 5 minute horn, do our penalty turns and beat the pants off everyone. The real question is can he even be counted as running the race? It would only seem that he could be counted even as a late starter if he crossed the finishline in the same direction that the original race started. For example, on an upwind start, if he finished the race and crossed the line going downwind, then it seems he would be counted as never even starting at all.