No, the game kept going from there. I had another several generations of family members beyond him, and all the generals were still out on the map, but nothing showed up in the family tree. I'm pretty sure I took a screenshot of it, let me go look...but apparently I did not. I still had a save from when I quit that campaign, but now that I reloaded the family tree is back, although King Robin and his descendants aren't showing. When he became king, he didn't have any kids so the faction heir tag moved back into the regular family. I'm not certain when the family tree reappeared; probably when the next king took the throne would be my guess. I played that up until 1297 AD, when I stopped to start my Venetian campaign. I had 40 regions and a truly massive modern army (pike, muskets, basilisks, etc.) and could have won the game within a couple of turns anyway.