I also am not know anything about psychology, but I know one thing. If someone betrays the Brotherhood (not the ideals like the Lyons did, or twist them like the Outcasts, but the Brotherhood in general) needs to be shot down by all factions of all games and then teleport him in SanctuaryRosaHouse. The cut house the named Feral Ghouls you meet that lived pre-war. It is an empty square with a placeholder door that does not open.

As for his goals, Caesar and Ulyses kinda want the same without the Could and Holograms. The problem with Ulyses is that no one will survive, so he basically won't achieve anything. Once his plan unfolds, what will he do then? Not to mention that while he will kill General Oliver, he will mostly wipe out the Legion. A faction that the Brotherhood doesn't care. So he will kill everyone except those he deems enemies. Probably that's why this ending was cut. It makes no sense.