All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If an inheritance is an estate, then it should be valued [according to market price] and then its value should be divided, or that it should be sold and its price should be divided. However, the agreement of the heirs is not valid without this son whom you mentioned, because he has the right to ask for his share in the inheritance so that he would be able to have accommodation either by buying or renting. Therefore, those who do not wish to sell should either give him the equivalent of his share from the inheritance or that they should give him a known portion of the house, or that the house should be sold and he should be given his share from it.
Allaah Knows best.