Cute,but that sure seems like a lot of cats for one household.

They likely had a litter from their lone house cat. That's happened to me on several occasions. Enjoy them as cute little menaces to society and then sell/give them away. Better to spay and neuter cats, but sometimes you get a cat that's already pregnant or it happens before you had a chance to.

From personal experience, a household with ~10 cats is manageable but that is where it gets hard (and I don't recommend it). Invest in a couple decent automated litter boxes, feeding set up so the cats don't crowd over one or two bowls. 4 is not bad. Makes for a fun little animal family. Hilarity always ensues. 1 is lonely, 2 is a rivalry, 3 is a crowd, but 4 is a silly family of prankster cats.

But then there is the mother who is off camera, so that's 5 cats. That's fun. Sibling cats who grow up around their mother become very caring and mature better. I had a scenario where my male and female kittens had kittens. It was so cool studying their family structure. Seeing the attachments the kittens have to the mother and father, and allowing it to grow to fruition is a joy to see, even if it's not always possible to keep the fam together every time.

Animal family units are awesome and I almost feel like every human family should have a protectorate animal family that is their duty to protect and nurture. If you can raise an entire animal family, you can do anything. Human families are narcissistic barbie playsets for most people, so this is less disturbing to me than a family with 4 children.

I was driving behind a SUV the other day with those "my family" stickers on the back window. There was one person, then taking up the entire rest of the width of the window were cats!