As you see in the curator's note up at the top of the profile, this person didn't really exist.
But the names of the two brothers are as they come down in the manuscripts.
We took the "Afallach" out because when it's in, it looks like there's a real person there.
This is the point where the real genealogies morph into the mythological -- here's Afallach -- Afallach ap Beli, {Fictional, “Urien and Modron”}