Well first of all, you and your brother should not be playing on the same account, as that is against Riot TOS (yes I actually read it), and your account can potentially get banned for that (I'm just warning you), so there is absolutely no need for this feature to be added, as it would only further encourage account sharing. What I suggest is that you each make your own account to play with different settings, so you won't have to change stuff around every single time. Hopefully this helps!
