Advice Needed:
So I had finally re-combined the Kingdom of Rus... and along the way, I took all of the Kingdoms of Volga and Crimea from the Cumans as well. I enjoyed great incomes, had ALL of my dukes/vassals at +50 or more opinion, and had Medium Crown Authority and Medium of every tax/levy. My king did not have good stats, nor especially great traits (no horrible ones either). My heir had GREAT stats, and all good or virtuous traits, in addition to being a duke with about 5 county demense. My 2nd son was cruel and greedy and ran a duchy of 3 poor counties.
When my king died, and my perfectly groomed heir took over, all of those vassals that were 50+ and some even 100+ opinion, dropped to -40 or worse and some even to -100. Of the roughly 40 duchies that were my vassals, just over 30 popped up immediately as "threatening to revolt." Within a week of taking over and before I could do anything to stop it, my greedy and cruel younger brother revolted and 4/5ths of my vassals sided with him. Needless to say I was pounded into oblivion in about 2 months and my younger brother usurped my Kingdom of Rus title. Leaving me with Volga and Crimea. Then within a week, nearly ALL of his vassals (the ones who sided with him vs. me a couple months ago) were begging me to join their war of independence against my brother.
WTF am I supposed to do here? I have the autosave to go back to right before my king died, so I can go back, but he's like 60 years old, and he's going to die eventually anyway. How am I supposed to stop this mass revolt, or at least make it less impossible to quell? I don't understand why they could love my lazy/content father with single-digit stats as king, but hate the strong/virtuous son with great stats and genius wife with 3 male sons already lined up to be heirs.
It doesn't look like my heir inherited much of my prestige (roughly 5k), and why on earth would they side with my shit-head brother who has like 4 of 7 deadly sins against me? Another thing I noticed was that several of my vassals hate the son for something the father did (raise to medium crown authority). I even tried to lower that crown authority in hopes that all those vassals would like me again, but they revolt long before the vote is in.
I know I should probably ask this in the main forum, but since I'm using this CK2+ mod, I figured it might be different enough from vanilla to make any answers I got there not as helpful. So... any suggestions?