Brothers planned to increase the number of games outside of Brisbane over time, and were strongly suggesting that eventually they'd play the majority of their games outside of Brisbane. They also wouldn't rule out playing games outside of Queensland, in fact they named Darwin, Wagga, Penrith, and IIRC North Sydney in their bid material as markets that they would target.
Apart from the fact that I find it extremely unlikely that all the members of their disparate clubs will drop their current allegiances to follow the Brothers NRL club in significant numbers, I don't really have a problem with the Brothers bid in theory (in fact I find the concept very interesting), but it isn't, and never was, a 'Brisbane bid', and as such it should be treated as something entirely separate from the goings-on in Brisbane. In other words, with or without a Brothers NRL team you'd still need another Brisbane team.
Besides all that, it's not clear if the bid is hibernating or if it's dead, as their website and all their social media died quite a while ago and, as far as I know, nobody has heard a peep out of them in a long time either.