That at least is something which poses some doubt. They weren't fertilised at exactly the same time. But they were developed in the uterus simultaneously, and born to the same mother, at the same time.Twin/Twins
Two individuals derived from two Fetuses that were fertilized at or about the same Time, developed in the Uterus simultaneously, and born to the same Mother. Twins are either monozygotic (Twins, Monozygotic) or dizygotic (Twins, Dizygotic).
Given that a pregnancy runs from fertilisation until birth, I'd imagine maffew and bro were part of the same pregnancy. Obviously the brother was late to the party, but it was still the same party.
But what I really want, is a DNA test to see if they have the same father. I'm opening a book on it if anyone wants in.