Is my brother’s widow entitled to maintenance from my father?

My brother's wife and her parents expect my family to care for her children after his death. Why can't she work to support them? Can my father divide his property as he wishes, and can he split it equally between his two sons while supporting my deceased brother's widow? Can my parents divide their property into three parts: two for their sons and one for themselves, due to concerns about their care if they give away two parts? Alternatively, can they split the property among all five children and keep one part for themselves? Can a ten-room house be divided among six people? After dividing the property, can my brother's widow move out and leave my elderly parents alone, and can she stop them from seeing their grandchildren? If my parents refuse maintenance as required by law, can the other party take legal action? What if my brother's widow doesn't get what she wants and starts mistreating my parents? Finally, how should we document our agreements? Do we need stamp paper, witnesses, and a lawyer?