By the power of truth, I, while living, have conquered the universe.
Posted by: forriedude
"When Dr. Halsey and Lieutenant Jacob Keyes visited Eridanus II in 2517 to study him,"
From the Halo Wiki.
Later in life, he viewed Jacob as a father figure. Not necesarily as a child.
He did not interact with Keyes, or even see him.
Halo Wiki talks bollocks, go read the books. John never looked at Keyes as a father figure, they hardly knew each other. John just admired his astronavigational skills.