(1) For the purposes of this Act every husband is liable to maintain his wife and every child under the age of 16 years whether legitimate or illegitimate, that she may have residing with her and wholly dependant on her at the time of her marriage with him; every father to maintain his child, every grandparent his grandchild; every widow her child; and the father and mother of every illegitimate child, their illegitimate child, until such child, grandchild and illegitimate child respectively shall attain the age 16 years, and when any needy person shall through age, infirmity or other defect is unable to support himself or herself every child and grandchild of such person is liable according to his or her ability to maintain such needy persons.