I d/k how the will was written but she has every right to write down what she pleases but the question is how it will hold up upon probate and tax issues and, since lawyers might be held responsible to third parties for legalmal in estate cases, esp without the doc in front of me, I d/k how this was written. I would step back from a client wanting the scenario you described and go over it with her-we do it all the time. I could see if maybe she set up some sort of a trust (they usually do these for homes) where upon MIL's death, SIL has it for her lifespan, then it passes to your daughter. There are always tax considerations in any case. However, the way you described it, I cannot see how there would not be any problems when probating this, with this "done" thing (menopause? sterilization? Ovarian cancer?...) with the issue of a female child. Just remember the Helmsley debacle where the estate plan was misdrafted and the executors were able to change what Leona wanted by arguing her way created tax problems. When we do wills, and we have thousands, we remind people nothing breaks up a family faster than money and if practical, consider an even split or at least a valid explanation (something like this, but in legalese: "Mary inherited $10mil from Grandpa and Sue $150K" or "Mary is a surgeon with a $5mil house in Grenwich and Sue has cancer battles and cannot work...so I am leaving Mary $15K (then put in a no-contest clause) and Sue the Remainder. So, the kin should discuss this with MIL.