Can an employer ask her maid to clean up her mother's flat once a week?
It is very clear that a foreign domestic worker may not work for another person other than her employer. The employer who requires her domestic helper to clean her mother's apartment once a week, say, may not claim to be ignorant of this prohibition because she will have made a declaration prior to the issuance of the work permit: "I shall not send the foreign worker to work for any other person..." See Employer's Declaration, item 8)
"I shall ... employ the foreign domestic worker to perform only household/domestic duties at the residential address as shown on the work permit." See Employer's Declaration, item 10)