Having watched them both speak, I think they are deep in grief. They look very sad and weighed down and there's no spark or joy there whatsoever.
This is what my friend looked like when she had a nervous breakdown, very thin, very drawn. People who are already thin, and in Kelly's case had buccal fat removal, then look even worse in grief or suffering because they have nothing to lose, and likely the effect of the weight loss medications is still keeping them unable to eat.
The problem is that you can only run so long at this weight before your body starts to get damaged. You are probably ok for the first year or two, if you have enough energy to do simple things, but over time, your body uses up the muscles, bones become brittle, the lack of vitamins show in your skin and hair, the colon may not restart working properly/digestive issues, and just being up and about starts to become hard work. The very difficult thing to endure is that often people who recover from eating disorders suffer the consequences of those things for years afterwards; you don't just bounce back once you start eating well again.
I think they can become healthier again and I just hope that they do as time passes, and that they are getting good medical advice on how to keep as healthy as possible and cause as little damage as possible.