What is the grandmother's share of the debt owed, and is it the house rent from the date rent ceased to be paid until her departure or until her death? And what is the share of each heir from the remaining debt, knowing that the son's wife was the sole beneficiary of the house after the grandmother's death?

Your grandmother is obligated to pay the house rent from May 2002 until her death in April 2006, and her debt is to be settled from her estate. As for the house rent from April 2006 to May 2010, it is incumbent upon your uncle's wife, who benefited from the house, unless your father or uncles undertook to pay the rent or agreed to her staying while being aware of the rent burden, in which case it is divided among them like an inheritance. If the two daughters did not commit to this and did not agree, then nothing from the rent is incumbent upon them.