Supplicating against unjust parent and sibling
2-1-2018 | IslamWeb
Question:
Assalaamu alaykum. My mother and little sister betrayed me with her housband. They took money that I gave them as a trust, and now they are also looking to share the house which I bought in the name of my mother even though they did not put any cent towards it. I feel betrayed by my mother and little sister and cannot do anything. I worked my whole life to get them out of poverty, and this is how they payed me back. I am in so much pain. Is it acceptable to supplicate against them, and how can I recover from this in an Islamic way? I feel very hopeless now. I hope to hear from you soon. Assalaamu alaykum.
Answer:
All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
It is allowable for the wronged person to supplicate Allah against those who have wronged him in proportion to the injustice done to him; however, it is impermissible to supplicate Allah against one's own mother, even if she has wronged him. The mother has an enormous right over her children.
Shaykh Ibn Baaz 
when he was asked about supplicating Allah against a father who has wronged his daughter, said, “It is impermissible for you to supplicate Allah against him; rather, you should say, 'O Allah, guide him. O Allah, protect us from his evil...’”
As for your sister and her husband, it is allowable to supplicate Allah against them in proportion to their injustice; however, it is better to refrain from doing so and to forgive them. To help relieve you of the effect of this injustice in your heart, remind yourself that the worldly life is the abode of trials and tribulations, that the Hereafter is the abode of reward and punishment, and that Allah is Just and never wrongs His creation. Allah, the Exalted, has urged His slaves to forgive and pardon those who wronged them and promised the wronged great rewards in return. He says (what means): {And the retribution for an evil act is an evil one like it, but whoever pardons and makes reconciliation - his reward is (due) from Allah. Indeed, He does not like wrongdoers.} [Quran 42:40] He also says (what means): {...and let them pardon and overlook. Would you not like that Allah should forgive you? And Allah is Forgiving and Merciful.} [Quran 24:22]
Allah knows best.