Gary, sorry to hear about your loss.
This is not legal advice, which I am not qualified to give, just some general info.
Assuming the property cannot be equally divided (in other words that it is indivisible), then it should be possible to force the sale at auction if the one who does not want to sell cannot or will not buy the others out. That threat is usually enough to get them to agree to sell. You’ll have to consult a lawyer for more info.