Sorry, I haven't had time to read the full thread, but if no one has already suggested it, and you aren't short of dosh, you could perhaps ask her if she'd like you to pay for her to try Wegovy or Mounjaro. Perhaps approach it by saying something along the lines of I know you've been trying really hard with Weight Watchers, and I've heard some good stuff about these weight loss drugs, if we can afford it, would you like to give those a try?
I'm disabled but have always struggled with my weight, and my DH has never complained about my weight, but knows being so heavy and unable to exercise upsets me, so if I bring up the subject, he always says, 'Well you know I love you whether you're fat or thin, but if there's something new you'd like to try, you know I'll support you in any way I can', and he does. For example, if he knows I'm trying to stay off the sweet stuff and he wants something, he'll go and eat it in the kitchen, in the car, or anywhere else that I won't see him, as he knows it's unfair to eat stuff in front of me that he knows I don't want to be tempted by.
On the other hand, you could always mention that you've read about someone (me) who in spite of not being able to exercise due to a disability, has managed to lose 1 1/2 stone, by using something called 'Slimpod' - Google it and read up about it so that you can explain it to her - it works to retrain your brain with regard to eating, and where I had tried every diet in the book, as it was something new and completely different, I decided to give it a try. You can get a 10 day FREE trial, and compared to Weight Watchers, etc., it works out really reasonable. After the free trial, if you decide you want to keep going with it, it costs £49 a month for just THREE months, and after that, it's free. All you need to do is listen to a podcast at some point every day, a lot of people, including me, do it at night just before going to sleep, I often fall asleep during it, although I think it's only 9 minutes long, but the information is still absorbed by your subconscious, and as I say, for someone who had a bad habit of comfort eating, and snacking while watching TV in the evenings, it's really worked. I've been doing it for 10 months now, and as I say, I'm barely able to get out of bed, so if your wife can exercise, that will of course help, although it really isn't necessary. I've actually stopped the evening snacking, although can have something now and again if I want to, just not lots, every night. However, I rarely have any desire for chocolate anymore, and that used to be absolutely IRRESISTIBLE to me. Oh, and just so you're aware, I have no links to the company, but just wanted to share the info as it's really helped me.
GOOD LUCK!