so, here's the thing:

Father tell's you that he was acctually taken away 60 years ago, not 10.

But Kellog, Kelogg, Ketchup(?) was a human right?

why did he not age or rather...die?

I don't quite remember where, but there's a terminal or holoband with Kellog's history and explanations. In short, he was more or less a Synth at the end.

Kellogg was a Cyborg and pretty much the proto-Courser.

Yeah, they talked a lot about Kellogg artificially extending his life. If you listen to the radio broadcast in his earliest memory, it talks about president Aradesh forming the NCR - which happened between the events of Fallout 1 & 2.

Yeah Cyborg (and therefore pretty dependent on the Institute).

Huh, I missed that. Would have been handy to have that knowledge when I went to the Institute and blew out Father's brains for kidnapping Shaun.

The info on Kellogg is on Father's terminal, in the area where his death bed is. He wasn't a synth, he was just heavily augmented with cybernetics. Though with Gen-3's being what they are, I guess there isn't that much of a difference.