There is an unspoken rule in dysfuctional famlies around loyalty. My guess is that your husband has been so severly traumatized and hurt by his upbringing that his denial of their abuse and sickness is in some way a defense mechanism for him. In some ways I am thinking that he hangs on to them so tightly because he knows they are the only ones who get him, and there is probably some truth to that. His situation sounds so horrific, I can imagine that for you, living with someone who has been so tortured by life , must be very very difficult. That being said, I hope that you know that you are not responsible for nor can you fix any of this for him.
I can imagine that you are completely worn out by all of this , 25 years is a very long time.
My heart really goes out to your entire family, I'm was really very sad when I read your post. YOu sound like such a strong and together woman to have survived, to have protected your children to the best of your ability under such tremendous stress.
My guess is , that you could use someone to help you begin to unravel , after 25 years of this, how you want to continue to live this second part of your life. Maybe some counseling is a good place to start. Maybe talk to your children about some family counseling. It's amazing that you survived.
Unfortunately, there is nothing you can do for your husband, if he feels or wants help, he will seek it, it sounds like that is not in his mind right now.
I hope you reach out, find a counselor, or a group , to help you begin to figure out where you are going now.
It took a lot of courage for you to give such and honest account of your life. I hope you keep posting. We are here to support you in anyway we can.
Sending you love and peace, Katie