Our culture doesn't understand what true honor and respect for parents look like and sadly I have almost lost hope that they will ever get it. I am quite sure there are adult children who think their parents are mean and controlling, when in fact the disrespect of the children affects the frustration level of the parent.
When a parent is treated as though they have nothing to offer in a relationships with their children, they sense that they are beating their head against a brick wall and they probably are. It is best to walk away and leave them to God, His ways are higher than ours and He has all power to carry out that which will bring them to the end of themselves.
Let God when you see that no one is listening! He knows just what to do!