I am not a teacher, just another yahoo on a message board. I do think it is fair to give him the grade that he earned. You surely would not keep your job if all you did was show up, right? You are expected to do a certain amount of work. You obviously made your student expectations clear as he was (presumably) the only student to complete zero quizzes.
Give him the grade he earned, and if he has an issue with it, the onus is on him to explain why he deserves to be treated as a special case.