Question: - Are Brahma, Vishnu and Shiv immortal?
Answer: - No. They are mortal. They also have birth and death. Brahma, Vishnu and Shiv ji also have mother and father.
Question: - Give us some evidence and also tell the names of their mother and father.
Answer: - In Shri Devi Mahapuran (published from Gita Press Gorakhpur), Third Skand, page 123,
Shri Vishnu ji praying to his mother Durga, says that – “Oh Mother! You are pure form. The entire world is originating from you only. We are existing by your grace. I, Brahma and Shankar take birth and die. We have (Aavirbhaav) birth and (Tirobhaav) death. We are not immortal. You are the mother of the universe and Goddess Sanatani and Goddess Prakriti.” God Shankar said, “Oh Mother! When Brahma, who was born after Vishnu, is your son, then am I, Shankar, who performs Tamoguni divine act, not your son, that is, you only have given birth to me too.”
It has been proved from this excerpt of Devi Mahapuran that the mother who gave birth to Shri Brahma ji, Shri Vishnu ji, and Shri Shankar ji is Goddess Durga (Goddess Ashtangi) and these three are mortal.