Pretty much what it says. Sébastien Le Livre was a 19th century middle aged family man who had gotten conscripted and then deserted from Napoleon's army, and now he's suddenly gained 3 queer older siblings (2 of whom look younger than he is) who are also scarily competent immortal warriors. I feel like there would have been at least several culture shocks there, and the poor guy wouldn't always have handled it well.

So 5 times Booker puts his foot in his mouth regarding his new immortal family.