A person had a child named Bl, another named Es, and one named S. The next was named You. They were a very unholy family.
Their children were shamed upon because their names spell out "Bless you."
Listen up, kiddo! So, this joke is all about wordplay. Get it? The names of the kids spell out "Bless you" when you put them together. It's funny because it's unexpected, and it makes fun of the parents for being unholy. You know, like when your mom tells you that you are special.