That was my immediate reaction as well, ninij, based on both what the mother-in-law said, and the husband, and especially with all the bodies of water in the area
.
Plus, I initially got the impression that Hazuki had not been working very much since the birth of the baby, but then I looked at her professional Instagram feed (thanks Daephine!), and realized that she had indeed been keeping busy (e.g., "For Glamour Magazine woman of the year awards @jilliandavison hair and makeup by me #hazukimakeup @glamourmagazine," Hazuki posted on September 8th at
https://www.instagram.com/p/BKGdwvwDWRx/; her last Insta post was on November 3rd).
I don't think she would have been able to work period, if she had been depressed to the point of being almost catatonic, as described by the mother-in-law. I think she just wasn't traveling as much, probably so that she didn't have to be away from Isse; she apparently spent many years traveling literally all over the world working at fashion shows, doing magazine shoots, etc.).
I really, really hope that Hazuki fled along with her adorable son, if not to Japan, somewhere, anywhere, so long as they are away from CS.