Who is the father of stored program?

Answer 1

That cannot be determined. The idea was developed and discussed by several of the engineers working on the ENIAC design during WW2, but nobody bothered to record who first brought up the idea. The idea however was not used on ENIAC as the design was already frozen and it was necessary to build what they had if they hoped to finish it before the end of the war.

John von Neumann was the first to document the idea on paper, so he is commonly erroneously given the attribution, but he definitely did not develop the idea himself.

Answer 2

It is unknown who first developed the idea of the stored program, but it was generated on project PX that designed and built ENIAC. The idea came up during discussions among the designers of ENIAC during 1944 and early 1945, but nobody bothered to take any notes of those discussions and by the time ENIAC was announced to the public in 1946 nobody could recall who had proposed the idea of stored programming.

Sometimes John von Neumann is improperly credited with the idea of stored programming because of the publication of a draft memo on the EDVAC stored program computer design that he wrote in June 1945. But he was only repeating ideas that already existed.