This app lets you restrict the volume to a reasonable level. It has premium features to lock the volume set minimum volume levels set separate limits for headphones or Bluetooth and set a PIN lock for kids.

Many children love to blast their movies and TV shows at full volume. This is true for both neurotypical and autistic children. If you configure it properly it can help protect their ears from permanent hearing loss.

I hope it gives you peace of mind and restores some sanity to your life as well!