IDDave, it looks like the middle tractor is showing a fair amount of white, which MIGHT indicate that it is a 1950 cub that was part of a limited number of cubs painted white to be used at dealerships to "demonstrate" how good the cub was.
The serial number (near the base of the steering shaft) would verify whether it could have been a "Demonstrator". Some folks find them collectible and more desirable/valuable.
The for right cub is either a '56 or '57.
I see cultivators attached as well as on the ground... you'll want to look for parts that are buried by "stuff" or dirt, and some that might be hanging from nails or the rafters! Some of the small parts could be worth more than the tractors.
Also, there is a huge difference in value based on a few things (not necessarily appearance):
1. Is the engine frozen?
2. Can you turn the engine with a hand crank (or fan belt)?
3. If it's connected to a good battery, will it turn over...or start?
4. Does it run? (Make sure it has oil pressure!!!)
5. Do the tire hold air?
The list goes on, but the first 2 items will determine the biggest difference in value. If the engine is frozen, it/they could still have value as a "parts tractor".
I would continue to post for advice, before you "throw them away"!
Give a holler, if you want. I'm about 2.5 hrs away. I'd be happy to discuss things with your brother, if he wants to contact me. I had sent you my contact info in a DM.