Any significance? Who knows.
Charles did have a twin sister, Clarissa, and his cousin was Clement G. Hurd (who later in life became the famous illustrator of GOODNIGHT MOON, THE RUNAWAY BUNNY and others) so I think it's weird that no one was making much of a stir about it. There were people in his life with the means and a motive to keep his case alive but they didn't. (We keep returning to that theme but it's a big part of the puzzle here.)
I somehow missed your post above. Maybe Mary Louise just had that effect on men ! LOL I think the suicide is just a coincidence.
I'm not certain we are going to be able to find an accident report by the police. It has sounded to me like he just bumped into a support railing. No other cars were involved, I don't know if they would have called the police in the 30s for something like that. IMO he was just a little drunk. He had gone there for dinner and stayed until 11:00 pm... Then hits a railing.. However, I think if he were planning to commit suicide. They would have found the car. Say, he jumped in the ocean or off a bridge.....car there. Even more logically, to me at least, he would have taken the car home to his wife. He would have let her have it and say taken a cab to the ocean. ????? What I would like to see is if the car was ever found........
As for his twin, I firmly believe they knew where he had gone and their intention was to enable him to do so. You can see what the newspaper reporting was like in that day. All that personal chat about Marie Louise's suitor. Her business went right out there on the street..... And nothing more than two articles on her husband's disappearance. Nah, that's not right. There has to be a reason for their silence.