Is the daughter-in-law obligated to serve her mother -in-law?

Answer

It is not Waajib for a daughter-in-law to be of service to her mother-in-law. However, while she will be rewarded for the service, it may not be imposed on her. Most certainly she will gain much thawaab for being of service to her mother-in-law. Furthermore, a good woman will be of service to her mother-in-law.