To get an idea of how well and how quickly brake fluid and power steering fluid mix, pour a little of both in a clear glass jar, brake fluid first…See how the two fluids behave in the jar.
Then I would flush the entire system thoroughly, after removing the contaminated fluid from the master, working the brake pedal full stroke during the process… I would repeat this in a week time…Hope for the best…
Just for fun, I might buy a couple of brake cylinder cups and drop them in a jar (the one from the mix test above) and see how long it takes for any deterioration to take place, just to keep all the experts honest…