91.3. A local municipality may, by by-law and in accordance with the policy directions defined for that purpose in its planning program, establish a program under which it grants assistance, including in the form of tax credits, to any owner of a single-family housing unit having the following characteristics:(1) it includes an accessory dwelling; and
(2) one of the dwellings is occupied either by a caregiver of the occupant of the other dwelling or by a person who is or was related by blood or allied, including through a de facto spouse, to the occupant of the other dwelling.