(a) The liability of relatives for expenses incurred in the care and support of a patient admitted under Title XIX of the Social Security Act [42 U.S.C. § 1396 et seq.] shall be as follows:
(b) The spouse, parents or children of a person not admitted under Title XIX shall be liable, in the order above named, for the expenses incurred in the care and support of such person; provided, that they are found able to pay such expenses. The Board shall take legal proceedings to enforce this liability, if warranted by the facts and circumstances.