Сын Авдотьи (имя неизвестно)
son of his wife's great-great-grandfather's sister, cousin of Konstantin Fedorovich
Son from Avdotya’s first marriage. He graduated from theological seminary, became a priest, and died early. First name, patronymic, confirmed last name and parish are unknown; Petropavlovsky is only a search option for the expected surname of the father ( S187 ).