I know someone who had a hoarding parent. Her children did call her and would visit but it was very unpleasant in the house as she had animals also. Finally they talked her into letting them build another house for her behind one of the children’s houses, fixing up the original house enough to sell, and moving her. She was upset at the loss of so many of her things that had to go in the dumpster. Part of her problem was depression after a divorce in her late 40’s. She still has hoarding tendencies but is happier now.
Anxiety can contribute to it, too. “Don’t you dare throw out that stuff, I might need it, it has value, don’t let it go.”