Is informing one's mother about the abuse and backbiting from the husband's family considered [a blameworthy act], and what should be done about it?

We advise you to be patient and to respond to harm with kindness, seeking reward [from Allah] and out of respect for your husband. It is permissible for you to complain to your mother to seek advice and guidance if you are unable to solve the problem on your own, as there is a legitimate benefit in that. However, if the intention behind complaining is merely to mention the faults of your in-laws, then it is not permissible.