I would like some advice on property allocation between siblings and parents. We all live in England. I have a sibling whom I love very much. We both get along with our parents who are divorced. We have seen families being broken apart from inheritance and properties and we, as a family, strategise together so that no-one ends up being treated poorly.
My father has a property ("A") and my mother has a property ("B").
Property "A" requires some payments so that it's made whole so it could be sold or developed further. It is a single house around 400 sqm. Our father has not made clear whether or not he will bear that cost.
Property "B" has an outstanding mortgage that our mother will NOT be able to pay off in her time / with her pension. The property includes the ground floor which is fine (where our mother lives) and the top floor which is in the process of being made into an 150 sqm apartment. This was the reason for the mortgage. The mortgage did not suffice for the full development of the top-floor and it is now half-way habitable - so there exists a need for an investment of say 20k gbp on top of the mortgage. This top-floor could well supplement one's income if completed asap.
The agreement that exists currently is the following: I will get property A and my sibling will get property B in due time.
Once it is needed, either my sibling or me can ask for a professional valuation of both properties subtracting any direct costs (like the outstanding balance on the mortgage for property B or the cost of making property A whole). Any differential one sibling will have to pay to the other.
Is this the best approach?
I am adamant that I want to be fair to myself and my sibling.
What other course of action / strategy should I pursue?