Carmion, the situation you described sounds more like an illness than just basic messiness. A friend recently had to sort the hoard of stuff her father had accumulated in their basement, and they were astonished to find hundreds of hand tools and pocket knives, collected in obsessive redundancy. They packed up a good set of tools for each family member and took the rest to sell at a flea market. If they had known of this stash, they'd have realized he needed help.

My parents were both children of the Depression and had a lot of stuff around. Mom had sorted through and discarded and given us a lot before she died. Dad just stuck broken or obsolete things in a shed where they accumulated, perhaps with the thought that they could be repaired. It was a huge job to sell and/or discard after he died.
Now I have a lot of stuff from both parents, and from great aunts who left antiques to me, and I'm slowly finding places to put all of this in this house I'm still remodeling (I moved in a year ago March). My kids know that where there are redundancies we are going to pack clearly labelled boxes and they'll go in the attic or garage for the day when the kids are ready to head off to a place of their own. Kitchen gadgets, bathtowels, some small pieces of furniture will all keep until they need them. I built storage space into my garage to avoid paying rental on units.

SRS