My sincere condolences on your loss.

OCD? Perhaps. Maybe not. When we remember things we often say "In the first place...in the second place and so on." In fact I think it was Aristotle who espoused this form of memorization. Take a look at your 'fridge or bulletin board. How neat is that? What I am saying is that this person of brilliant mind may have needed the items so organized to keep himself organized.... and secure feeling and aid his memory.

Did he have many interests? Lots of little projects that may have been interrupted or derailed? All these "things", crap as you call it, were part of his life. Sure it is unconventional, a deviation from what we believe to be the "norm" but not something to grieve over. If we can't see the treasure in some item or a whole host of items doesn't mean that they weren't treasures to him. And don't sell him short. There may be treasures there that would be appreciated by others.

Long term financial insecurity may also be at the root of situation too. The facial tissue thing does bother me somewhat. Was he keeping an unused corner available for future use?

As mentioned above by others depression, which is epidemic these days, can lead to such behaviors, I know. A broken heart, an unbearable loss, dreams gone awry might diminish one's ability to cope with the mundane things of life. A lot of other factors can lead to the "Warehousing Syndrome". Chances are that if someone were to have arrived to help him "tidy up" he would have had none of it. To him it WAS order.