Answer:
(Fatwa: 411/335/B=1431)
You should not be obsessed with the doubt magic and witchcraft. After Isha salah in the state of wudhu recite ya Aziz (يا عزيز) two hundred times with durood 3-3 times before and after by turning your face towards the house of your son-in-law. In-shaAllah it will soften his heart.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband
