N.J. Stat. § 30:4-66
Every person supported in a State or county charitable institution or other residential functional service pursuant to section 13 of P.L. 1965, c.59 (C.30:4-25.1) shall be personally liable for his maintenance and for all necessary expenses incurred by the institution or other residential functional service in his behalf and the father or mother of a child under 18 years of age, severally and respectively, being of sufficient ability, of every person so confined, whose estate is not sufficient for his support, shall support, and maintain the patient in the institution or other residential functional service, as the case may be, in such manner and to such an amount as the court shall direct pursuant to subsection c. of R.S. 30:4-60 in the case of mentally ill patients, and in the case of developmentally disabled persons, as required pursuant to subsection b. of R.S. 30:4-60. But no payment shall be ordered to be made by a chargeable relative 55 years of age or over except with respect to the maintenance of his or her natural or adopted child under the age of 18 years.
N.J.S. § 30:4-66