Good morning from Texas! My family set-up is: my father, my mother (his wife), his “main” girlfriend and 2 “secondary” girlfriends which get changed usually every 2-3 years. Yes, we all live together in the same house - though it’s a big house - so it doesn’t feel crowded. It’s not a religious thing at all, we’re atheists.
$$$, taking care of himself physically and having an attractive personality would be my guess.
So is your father the money maker in the home, or does everyone work and bring in money? Curious about the economics of that