I am dealing with elderly in-laws in their 80s (not hoarders though) but they should no longer live or drive by themselves. No amount of calm discussion makes them even consider trying any other option and they get very offended if the topic even comes up. I am advised that as long as they are "of sound mind" that we cannot really do anything to force the issue. They are adults making their own decisions until unfotunately something happens like a bad fall or car accident. Seems like if it is a really bad situation with your parent's hoarding, that neighbors or someone anonymous would call them in on a code violation. That's what usually happens in my hood when people let their houses or yards go awry.