I might sound like a terrible person but I don't believe that she is so sick that she can't work. I believe she is sick and that she has to deal differently with her time but between hardly not working and working full-time is a long way. She could do so much better. She just won't because she is lazy.
She has always been lazy and self-centered and no illness will change that, it has just given her a shield to deflect a lot of criticism.
Apologies for answering your post so late but I've just seen it.
I truly don't think we know when MM was diagnosed with pulmonary cystic fibrosis. We know when the palace made the acknowledgement but not when she was diagnosed.
Pulmonary cystic fibrosis is an extremely serious disease, it will kill her. Usual life expectancy is under 50 years depending the growth of the disease and likely she will need a transplant if she's to live longer.
Frankly, unless we or our loved ones live with this disease few of us know how much it impacts everyday life.
We should all be a bit kinder.