child support from a filipino father to an italian citizen child

My brother is married to filipina who has acquired an italian citizenship. They were married here in the phils and lived in italy for 2 years and half. They had a child who was born in italy and became an italian citizen too. My brother has not been an italian citizen. when they separated due to the attitude of the wife and the parents his passport were hidden and he was forced to have a new one and then went home to the Philippines. Now the family of the wife and the wife is asking for the support of the child. But my brother is still jobless now and they are forcing us to support the child in any ways. they are even forcing my brother to sign a paper for child support. Atty. is this legal and can they really force my brother to support the child even though the child is italian citizen and my brotheris here in the philippines and jobless? do they have the right to force us brothers and sisters to support their child or our parents??