My father passed away last year and his wife controlled much of his clutter although his sheds were horrific and he had 2 terrible rooms in his house. We spent days cleaning junk out of.
My husband's mother is also a clutter bug and if I am still around when his parent's pass, I will suggest burning the place down.
His father once said to me, it is all her, not me. He could grab a small box and put his things in it and it irked him that whenever he wanted something of his out, she had no room for it. I am not kidding when I say that his words broke my heart.
My husband's mother said she has been going room to room and giving things away to nieces and stuff which I hope that is true. She seemed disturbed when my husband told her that when cleaning my father's house, much went to charity or in the trash. She gasped... but that is what happens in most cases when people who keep clutter pass on.