What is the ruling on parents asking their son to divorce his wife, whose relationship with them has deteriorated, and the relationship between them and the wife has become strained due to family problems, and what should the son do if his income does not allow him to move to another house?

Family problems and disagreements are natural, and the issue lies in how they are dealt with. If you predominantly believe that the cause of the problems is magic, then you should perform ruqyah (Islamic exorcism). There is no harm in presenting the matter to scholars specialized in ruqyah, not to charlatans.

If your wife's treatment of your family was good and then changed, the reason might be frequent harm inflicted upon her by your family. So, be patient with your situation and endure whatever comes from your parents. Advise your family to treat her kindly, and oblige your wife to respect your family. Beware of letting her lead you to disobey your parents.

A wife assaulting by hitting is not permissible. She must repent to Allah, seek forgiveness from whomever she assaulted, and apologize to your father.

Obeying parents' demand to divorce the wife whenever there is a disagreement is not permissible, unless there is a valid Sharia reason, such as her lack of rectitude or her harming them.

Renting a separate house for you and your wife is preferable if you can, to avoid problems. It is not permissible to accuse your wife of theft based merely on suspicion.