Section 17A. (a) Section 18 of chapter 184, section 17 of this chapter and chapter 239 shall apply to a lawful housing occupant who is a client in a program of residential care and services licensed, funded or operated by the department of mental health and who: (1) pays the program for such residential care and services; (2) receives care and services from the program in a housing unit equipped with a kitchen and bathroom; and (3) occupies the unit either alone or with the occupant's family, as defined in the regulations of the department.