Okay, this may seem petty, but... while I totally agree that Jack should get a third of the available estate, it's important to realize that there are also tax consequences which are different. Inheriting a third of an estate is one thing. Giving someone a third of what you have inherited may involve gift taxes.

So while I agree that the sharing should happen, the three of them ought to consult a tax attorney to ensure that they also share the potential tax consequences to each of them of doing so. Fair is indeed fair.