Does a divorce take effect if the father frequently swears by divorce without knowing what he is swearing by, and he does not intend divorce in its actual meaning? And is it permissible to retract the oath with money?

You did not specify the formulas used for divorce. If he divorced her with a pronouncement of immediate effect (e.g., "You are divorced") on three separate occasions, then the wife becomes irrevocably divorced from him, and she is not lawful for him until she marries another husband. However, if he divorced her by way of an oath (he swears by divorce and then breaks the oath), the majority of scholars hold that it constitutes a divorce. In contrast, some scholars are of the opinion that if someone suspended divorce with the intention of threat or urging, and then the condition he suspended it upon occurred, divorce is not binding upon him; rather, he must make expiation for his oath.