If this is a long time incapacity people may have forgotten, it does not need to be the same person that makes medical decisions and it could be someone other then a sibling.  

A sibling who isn’t capable is demanding to get paid to manage the properties because no one wants to pay a property manager, one thinks they can increase rents to market value despite them being in disrepair, another is focused on not selling because of taxes and 2 want to sell. 

You're in the Ohio market where it's definitely possible to team up with maybe a sibling and get a property when you're 21 ish.

My friend Jose.  5 siblings 20 to 25, one baby, mother 50 living in 1,200 sqft.  

He is 22 and lives at home with his parents and 3 other siblings. 

My parents are retiring in a year and are considering selling their house and buying or renting a place close to me and a place close to my siblings who live in another state.

You could offer the cooperative siblings an amount in exchange for her signing a quitclaim deed -which is a simple one-page deed granting all of their interest in the property to you.

You can start with your own kids or siblings, raise tiny amounts of money.

If you own part of the new property as a tenant in common with your sibling, it is actually two pieces of real estate.

This will likely eventually lead to resentment from the sibling receiving the lower valued property.