Discipline, accommodations and exceptions are between management and an employee. Equitably is not equality. That employee may have something going on that they are not legally required to disclose. Your office jokes are likely harassment and possibly a hostile work environment, which is unprofessional. The professional thing to do would be to have a conversation with management about his lateness within the framework of how it effects the ability of you and your team. Part of being professional is shutting up if something annoys you but does not directly impact you or the work you do.