6.—(1) For the purposes of section 37(1)(c) of the Act (condition of entitlement to an invalid care allowance that the severely disabled person is either such relative of the person caring for him as may be prescribed or a person of any such other description as may be prescribed) the relationship which the severely disabled person is required to bear to the person caring for him is that of—
(a)lineal descendant or ascendant in a direct line;
(b)husband; wife, step-father, step-mother, step-son, step-daughter, brother, sister, half-brother, half-sister, step-brother, step-sister, aunt, uncle, nephew, niece; or
(c)father-in-law, mother-in-law, brother-in-law, sister-in-law; son-in-law, daughter-in-law.
(2) Reference to any such relationship as is specified in paragraph (1) of this regulation shall be taken to include any such relationship by reason of adoption and also any such relationship as would have subsisted if some person born illegitimate had been born legitimate.