Do u think that...

Different mothers? Odd gene in the family pool?

-- Ew lover, you gonna make me clutch my pearls --

It happens. Sometimes siblings take after each parent rather than resembling just one. Especially if there are multiple siblings. For all we know there may have been several other brothers or sisters in this family.

Regardless we're supposed to see the actors as the story's characters rather than Bettany and Graham.

Stephen Graham could pass as Brain Cox's son - Paul Bettany certainly couldn't. We didn't see their mother, though.
The cast was excellent nevertheless, esp. Bettany and Strong.

🐺 Boycott movies that involve real animal violence (& their directors) 🐾