Article continues below advertisementJohn F. Kennedy's grandson Jack Schlossberg was struck with grief at the funeral for his sister Tatiana.The heartbroken political commentator attended her memorial in New York City on Monday, January 5, alongside his mother, Caroline Kennedy, father Edwin Schlossberg and sister Rose. Tatiana's children, Josephine and Edwin Moran, and husband, George Moran, were present as well.Article continues below advertisementSource: @jackuno/InstagramTatiana Schlossberg's brother, Jack, looked heartbroken at her January 5 funeral.