What topic does author, David Sedaris, discuss in the essay titled, Company Man?

In his first essay, Company Man, David Sedaris discusses he and his partner Hugh's experiences as hosts, with a particular emphasis on when three of David's sisters come to visit them at their home in Sussex for Christmas 2012. This is an important visit for David as they are all getting older and he wonders how many more times they will be able to do something like this all together.