The more I think about it, the weirder that phone call from Douglas to Thomas was. He obviously felt safe enough to taunt his father but if Flo hadn't confessed, life would have gone on, he would have had to go home to Thomas and Hope. Then what?
I know TPTB would never actually take advantage of a real story opportunity but if Thomas had killed Caroline, Douglas's behavior would make more sense. Or maybe he mentally abused her into committing suicide and the aneurysm was just a convenient fiction. Or maybe Caroline is still alive but committed to a mental institution. I mean, if you're going to make a legacy character a psychopath, you might as well get some stories out of it. 🙂