not enough time to work on the car

No one really knows what to keep and what to toss. If you have a imagination that predicts a Thunderdome like society, you have to consider what is involved in storing things for that eventual time. Next question is do you have the resources to protect it from thieves? I simply pray I don't live to see such a time.
I am sorry you lost a family member. My mom is now 80.8 and in poor health. Dad is 80.2 and she is wearing him out trying to go through and clear some stuff. Granted most of what she has accumulated through the years is paper, B-day cards, Mother Day cards, financial records, etc.., but... several large totes of it. She says she wants to clear clutter, make it easier on her kids. If my dad had accumulated a lot of stuff like your uncles' , You and I and would have no idea where/when he acquired it. I told mom, "I might enjoy seeing a card that I bought or made for you in 3rd grade again". I shouldn't have said that. Just made it harder on her (Dad told me so). I'm sure you have enough of your own stuff for someone to deal with some day. If you sell the uncles stuff on ebay, he just might look down and ask, "Why didn't I do that?", or he might say, "That is exactly why I didn't do that".
Off into left field before I end. My son-in-law watches so much TV like Storage Wars that it got him. They bided and won a storage bin 2 weeks ago. They put a whole day into sorting and hauling some stuff to the dump. Then the made a trip to the pawn shop with the jewelry they found, and got more than there original investment. Next weekend they are off to the auction where there earned 1.2 times their investment. I figure he is really hooked now. LOL
Good luck to you.