The provisions of this chapter shall not apply to a child employed by his parents, grandparents, or a person or persons in place of his parents or grandparents, employing his own child, grandchild or a child in his custody, who furnishes full maintenance to such child. Nor shall the provisions apply to a spouse working for the other spouse on a volunteer basis when the spouse who works does not expect or claim any pay for the work, other than the support derived from the other spouse’s profits in the business.