I think we think of Jack and Kawalsky as friends for a long time also due to The Gamekeeper, they were on a mission together in 1982, which implies they have known each other at least that long. Whether they kept in touch over the years is open to interpretation as in the original COTG Kawalsky says as you that he didn't know Jack had a son, however this line has been edited out of the recut. Which canon is canon!??! *g*

(and they were pretty chummy, hand holding and such in Enemy Within, maybe Jack is touchy touchy, who knows)