@Former-Member, that might be a worthwhile option down the track, but until we've actually been able to look through everything ourselves we don't know what's "unwanted". We've got a pretty good idea by now of what's in the house, but our Dad's shed is packed full, to the point where there's a narrow walkway in, but no access to most of what's there. We suspect we could furnish the house over again from its contents, as long as we were happy to eat at a well used but very solidly made workbench... He was mostly very orderly about how he stored his things, but he had a lot of them. The shed may turn out to be where the stuff we really want is, for the most part. The house furnishings are either "heirlooms" or "junk" with not much that's in between, so those things have been the easy part of the decision making.
Everywhere we look, there's lots of clutter but a few real treasured pieces mixed into it. Even among the scrap metal, we found a complete antique fireplace fender, and parts of a second one. We'll probably take the "parts" one for our Victorian era house, and let my sister have the complete one. We also found some classic car parts, and owning a classic ourselves, we know that they will be snapped up quickly by enthusiasts.
Bleah.... sorry, it's all pretty overwhelming. So many decisions to make, and with so much else going on in the family, it gets to the point where the brain just shuts down. I'm seriously considering the idea of doing neat outdoor stacks of whatever's either rubbish or weatherproof enough not to matter, just so that we can clearly see what's what. We started doing that with some of the items from the "scrap metal" corner, and it was good to be able to easily look over it with my sister and go "Well, I'd like that and that, this will be worth selling, that's junk".