Making a house un-sellable

Hello,
My wife's grandmother has provided for her mountain house to go to her two daughters. She is now concerned they will sell it for the $$$ and wants to protect it. What is the best way to protect the mountain property. Grandma, trusting my wife will never sell, wants to include her with her two daughters on the will with the provision that 'all parties must agree' prior to anything being sold (on the mountain). Any suggestions or guidance is welcome. Regards.

Put the property in a trust with instructions of no sale.
The way that you propose is dangerous because if your wife dies first, the 2 remaining will have the say to sell.

Leaving the house "for the family" may sound like a nice thought, but there are real issues to consider in doing so. The issues include:
1. how much control does grandma want to exercise from the grave, by directing what can be done with it and who has to agree to any changes in that plan, and
2. to whom does she want to leave the assets she has accumulated?

A mountain home or vacation home may have had great meaning to grandma but it be wholly impractical to maintain it "in the family". With more and more families spread out geographically, and the demands of work and caregiving, getting to the mountaintop home from 3000 miles away may be costly and difficult -- even if there was time to do so.

And any property can be costly to operate. There are taxes, maintenance, repairs, insurance, etc. to be considered.

If grandma leaves it to all 3 with a provsion that it requires unanimity to sell the property who pays for the upkeep? Suppose 1 or 2 have no interest in it? And who gets the benefits of the house? For example, who decides who gets it for July and August? Who lives right nearby and would use it?

I suggest that she see a lawyer and discuss the pros and cons of the alternatives open to her. What seems like a nice thought to her and you may be a real burden to your mom.

Reairs, etc. inaccessible to