Brawly is in his late twenties, so probably more like brothers. In the original fic, he was married and had a 3 year old child, although I haven't decided if I'll keep that or not.
Also, since it's relevant, the shrine of Kyogre is on the western shore of Dewford Island, across some rocky paths from the town. Brawly keeps a sacred artifact known as the Sapphire which should allow him to communicate with Kyogre from her shrine; he hasn't been able to contact her spirit since the drought started. The Sapphire used to be passed along a specific family line, so with Takusen being an orphan, he could be from that family.