An Inquiry Into Greg

So, I powered through the series in about a week and fell in love, but found myself asking - how much did Greg know? It's clear he had no idea Rose was Pink, but how much did she ever wind up telling him? Does he know gem history at all, or even what happened during the war? Or does he just know there was one and "Rose" was the rebellion's leader? I feel like I missed this info, and rewatching "We Need To Talk" has me really wondering.