"Untypical" is not the same thing as "unreasonable". For many people who aren't you, an extended family living in one house is a normal course of affairs.

My household is 5 right up until any family come to visit, and then we'll be 7+ for potentially 2+ weeks

I mean he’s paying for two lines. So make it two four person households.

Okay, so make that a handful of college students sharing a rented house (on a single lease, not separate units): they're all hugely into video games and want to be professional streamers one day, and they all have very different schedules, so for most of most days at least one of them at a time is streaming in 4K to a Twitch channel.