Hi Essnell,
I don't know if I am the only one, but I am a bit confused by your post and like others, would be happy to help if possible.
Your great grandfather is unknown.
He had a child with a woman (you know about her).
The child is your grandfather born in 1922.You know about him.
You have a DNA match to the Murray family,
Frederick MURRAY may be the great grandfather you are seeking.
Is that right?
Sue