How can the three brothers not suffer from separation and how do they need to write family conditions?

An old man has a room in the house and the other three brothers share it equally. If it can't be divided equally, it will be the old man's. If the property belongs to the elderly for one month, the floor of the house can also be drawn by lot. If the property belongs to the elderly, the elderly will arrange to rent a house or live by themselves, and then the three brothers will take turns to take care of it every month until the elderly share it equally after a hundred years.