Husband accidently poured power steering fluid in the brakes

Hello,

Putting power steering fluid into the brake system can do major damage. As when a petroleum-based fluid like power steering fluid gets into the brake system it can damage the master cylinder seals and other components.
As you would not know what internal damages might have caused by the fluid, it is recommended to change the major components after doing a complete flush of the system.

Here are couple of helpful articles:

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system
https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

Keep in mind that the reason this is recommended to change the components is that you would not know when any of them can fail due to the fluid mix-up. As the brakes are a major safety component, it is best to change out these parts.

Please let me know of any questions.
Thank you.