Subject to subsection (b) of this section, the Secretary shall adopt regulations, guidelines, or policies implementing the federal Family and Medical Leave Act of 1993. The regulations adopted by the Secretary: may require an eligible employee to use other available accrued leave concurrently with family and medical leave; and may not limit, to less than 24 weeks, the aggregate number of weeks of family and medical leave that two employees who are married to one another may use during a 12–month period for: the birth of the employees’ child; the placement of a child with the employees for adoption or foster care; the serious health condition of the employees’ child, if the child is a minor; or the care of the employees’ adult child, if the adult child is incapable of self–care.