Ernesto, an overseas Filipino worker, was coming home to the Philippines after working for so many years in the Middle East. He has saved P100,000 in his savings account in Manila which intended to use to start a business in his home country. On his flight home, Ernesto has a fatal heart attack. He left behind his widowed mother, his common-law wife and their twin sons. He left no will, no debts, no other relatives and no other properties except the money in his savings account. Who are the heirs entitled to inherit from him and how much should each receive? (2008 BAR)