How is a house, part of which was built with the father's money and the other part with the son's money, divided between the son and his sisters after the death of both parents?

The floor built during the father's lifetime belongs to the father and becomes part of his inheritance after his death. The questioner has the right to take his debt from the inheritance before its distribution. As for the floor built on top of the heirs' house, if the heirs gifted the rooftop to the questioner, then the house belongs to him. Otherwise, mere permission does not make him the owner; rather, the rooftop is lent to the questioner for a specific period, after which the heirs must pay him the value of the construction.