SEPARATED WOMAN, DIED, HUSBAND WITH "QUERIDAS" WANTS TO OWN ALL PROPERTIES.

I would like to ask regarding my mom in-law's situation. She passed away days ago, and ever since i and my husband got married i have known their family situation that their dad never supported them-his mom, and his two siblings, whether financially or even his presence in important matters. Their dad has been living with different women for the past 18 years, and now that their mom died, he wanted that all their properties (house, money,etc) would go to him and his present "querida". Do my husband and his siblings have the right to own the house? and what lawsuit/s can be filed against their dad, aside from having queridas? what articles and sections of the Philippine Constitution did their dad violate?
Thank you.

what they should first ensure is that they take control and possession of the properties to force the father to have to take legal action.

unfortunately, the father may end up with more than 50% share of the properties because the mother did not take legal action to remove his ownership of the conjugal properties.

in a case i know of, the children prevented their father from exercising any right over the properties, and the case dragged on until he died.