How can one deal with a mother who rejects her daughter's marriage based on the words of soothsayers, and asks her to separate from her husband whom she married with her consent?

If a mother prevents her daughter from marrying a suitable man (kufū'), she has acted wrongly. The guardian (walī) of the woman is her brother. If he refuses, then her nephew (her brother's son) is the guardian. Her marriage with someone further in guardianship, while a closer guardian exists, is a point of contention among jurists.

The mother and brothers should be advised to fear Allah and to avoid separating the spouses. The mother's belief in soothsayers is a great evil from which she must repent.