Id almost be willing to bet my life that there are simulation games out there that are just about brushing hair. I'd bet you if you were to search "hair brushing Simulator" on Roblox you'd get dozen of results. If you want to know if there are any good quality and well made hair brushing simulators out there, then I wouldn't bet on it. However, you might be able to find a few half decent quality or somewhat coherently put together games if you search hard.
For whatever reason my keyboard just had a seizure and decided to post my reply before I was finished, but anyways I was going to say that after typing all that out, now I too have a strong urge to find and play a stupid hair brushing simulator game.