Helen: It was wrong of my brother Mark to tell our mother that the reason he had missed her birthday party the evening before was that he had been in a traffic accident and that by the time he was released from the hospital emergency room the party was long over. Saying something that is false can never be other than morally wrong, and there had been no such accident -- Mark had simply forgotten all about the party.
The main conclusion drawn in Helen's argument is that it was wrong of Mark to tell his mother that he had missed her birthday party as a result of having been in a traffic accident.