Thread:RABNerd VP/@comment-44402876-20200711182723/@comment-44402876-20200711183257

No, they're not brothers.

Thomas Wayne Jr. is from Earth-3 (another dimension), and while he had a brother called Bruce Wayne indeed, he was killed at a very young age. Later Thomas Wayne Jr. became the Owlman, a criminal mastermind.

Meanwhile, Bruce Wayne (from Prime Earth aka the mainstream dimension) never had a brother.

On the Crisis on Two Earths arc, Earth-3's Owlman met Prime Earth's Bruce for the first time and they definitely didn't see each other as brothers either.