Good walkthrough. I think a lawyer would happily take the case on contingency to get a cut of a big easy settlement, but other than that everything you wrote sounds likely
The contract lacks consideration and would not be found valid. No contract, no damages, no contingency.
I’m not a lawyer at all, but i just googled the definition of “consideration” and i don’t see how it applies here. This is a statement of how his property should be bequeathed after his death. People don’t will their properties to people in exchange for benefit before they die.
Consideration means both sides need to give something in order for a contact to be formed. Asking “can I have x”, and the other side saying “yes” is not a contract because there is no consideration. This is day 1 law school Contracts stuff.
A will requires a document and cannot be formed orally except in very specific circumstances that do not apply here.