This is not at unusual as one would imagine.
“Dr Evan Harris, a former member of the Commons science and technology committee, said: “In A&E departments up and down the country, patients without capacity, such as those drunk, drugged, psychotic, confused or with dementia, are treated seemingly against their will, day in and day out. Learning disability coupled with needle or hospital-phobia in a patient with cancer is unusual but is a relatively routine matter for clinical ethics.”
They are not saying she is temporarily incapacitated, but that she is permanent incapable of understanding her decision. They are also not saying she is incompetent for other life-affecting decisions.
I read the whole article and find it incredulous that they can forcibly treat her without invalidating her competence in any other aspect. This is NOT a temporary ruling - but applies to this woman in perpetuity - she is ruled incompetent to make any decision the doctors disagree with.