It's quite fascinating actually. I don't know whether my brother has always been a hoarder, but he was quite ill at one point, I put it down to his illness at the time. Through his illness he had to return to live at the family home, had to go through his property for anything that needed to be kept, then got a clearance firm in. Now he has started hoarding at the family home, he's limited to two upstairs rooms, but it kind of feels he has the hoarder instinct in him and always will, something I've discovered about him that I never knew and find hard to understand.