So if the rabbi will go to his own brother’s or close friend’s party, I think he should make the effort to show up, even if just for a few minutes, to the simchas of those who respect him so much.
i also think that is a good idea, but in your own words: “it’s your choice.” you dont know why he didnt go. YOU dont know upon what his decision was based. If you claim to repect a certain Rov, then i would hope you actually do respect him and its not just words.
Rabbi Avigdor Miller, tzl went to very few Simchas, even of his Talmidim. do YOU know why? I dont. I can surmise, but i dont know. But I DONT QUESTION HIS DECISION.