During Reb Itche Mates and Rechele's wedding in Satan in Goray, Levi, Reb Benish's son, acts as "master of the sacrament":
Levi, Reb Benish's younger son, he that belonged to the Sabbatai Zevi sect, was the master of the sacrament. Pale with the fear of punishment that he, not Ozer, was filling his father's place, the narrow glass in his hand trembled, and the wine spilled over his fingers[...]
Satan in Goray, part 2, chapter 1: "The Wedding" (translated by Jacob Sloan)
Why is Levi afraid of "punishment" here? Punishment from whom? And why would Ozer take Reb Benish's place - contrary to his name, Ozer's never been very helpful, and seemed to have no interest in taking a rabbinical position. I'm not aware of a tradition that states that the older son of a rabbi must be the one to continue his father's service. Why would Levi be worried that Ozer was supposed to take this place?