Division of mom's property

I have a question as to how to fairly divide up our "inheritance". Even though I don't see it as an entitlement, I would really like someone to give me their opinion. Here is the story. Dad died 3 years ago leaving mom and the house. There was really little else except for a life insurance policy that was divided up between his grandchildren. At that time, my eldest daughter and her family of five moved in with mom and they paid only $100-200 per month rent and agreed to fix up the house so that we might one day sell it to them or someone else. Mom also helped them with their bills. This went on for about 1 year, at which time, my daughter's husband got violent, destroyed part otf the house and hurt his wife. However, instead of moving them out, my sister decided to remove mom from the house so mom moved in with my sister. For about another year (and after counseling, etc) my daughter's family lived there for a minimal rent with no help from mom and they managed to save enough to buy their own home. But once they moved out became angry because we would not give them any money back!!!! Now when they moved out they trashed the house. My other daugher moved in by herself, after taking 3 weeks to clean, disinfect and generally make the house livable again. It needed a fumigator, needed new bathroom wall (because the wall had disintegrated from the tiles falling off and no one fixing them) and the house was filthy. They had also left standing water in the basement, bags of open garbage in the basement and the house was infested with fleas. She had to rent a dumpster to take away all that was left in the house. Two years later, my daughter is still painting (to cover crayon drawings on the wall) and replacing windows (as they were all broken) and porch screening which was all torn up. (When my parents lived there everything was in good condition)

The house is already in mine and my sister's name and has been for many many years. Anyway, now we are looking to sell the house -hopefully to my youngest daughter..who can pay only about $80,000 for the house. At the time she moved into the house a realtor said that it was worth only $72,000-80,000 but now since my daughter has put all of this work into it, it may be worth more.
Any suggestions as to how to make this equitable. My sister wants to make as much money on the house as possible and of course, I would like my daughter to be able to get the house if she can. And how much is all of the work that my daughter has done on the house worth. I have kept track of all of the supplies that she bought so I know she has spent more than $1,000. But also many, many hours of labor.
Any suggestions?????