The evolution of a parents brain

When our children are small, our brains function at maximum level, unrivaled, we seem to have unlimited knowledge.
What happens as they grow older is bamboozling to me. I don't know if it is from the strain of daily living or all the markers we sniffed when we were younger, some kind of brain damage occurs.
By the time they are teenagers our mental capacity has diminished to the point of no-return. We know next-to-nothing, actually, that is giving us too much credit. It is a wonder we actually survive during these years, cooking, cleaning, showing up to work, breathing. It is a good thing we have our children to look after us.
Our brains are astonishing! They can actually repair themselves. What we thought was irreversible brain damage is miraculously reversed. By the time our children have grown into young adults we have almost returned to our original level of exceptional cerebral aptitude.
Thank God our children grow up, or we would be "brainless" for the rest of our lives!