As I read in a FATWA, The prayer of a parent for his child is answered as reported in an authentic narration reported by Ibn Maajah.
Please clarify, this is for a live child or the dead child is also included. Further, if the married daughter died in the age of 26 years, will be considered as CHILD or otherwise.
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
This Hadeeth includes every child, be it living or dead, young or old, married or unmarried; as there is no evidence, to the best of our knowledge, to specify this merit for a particular child apart from others.
For further information about things by which the living can benefit the dead, refer to Fatwa 84938.
Allaah Knows best.
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