If one’s mother-in-law’s or mother’s attitude towards the poor especially the servants is very strict and it is really disturbing for the other person, then what is one supposed to do?
The best way to change a person is to become an embodiment of what you want him or her to adopt. You can become a great source of reforming the attitudes of your mother or mother-in-law by setting an example yourself in dealing with servants. This I think can prove most effective. But you will have to be very patient. People take time to change. Always keep in mind that your duty is to persist with what is right and to leave the rest to Allah.
The other thing you can do is to console and sympathize with servants whenever an incident takes place which hurts their feelings. Affection and sweet words do help.