This is a very sad story but as others have said Ian Duncan clearly doesn't understand women's health sufficiently to know that there is no screening programme for ovarian cancer. It is sadly very unlikely that his sibling's cancer could have been picked up at an early stage even if they had had health insurance, engaged with healthcare providers, etc etc.
However. What this does usefully illustrate is that in failing to stand up to aggressive activism, the medical profession's leadership has totally failed both trans people AND individual clinicians who are having to deal with the consequences of this on the ground. Medics should never have allowed people to erase or falsify information about one of the most important human biological variables in their health records.
The profession has colluded in (and arguably created in the first place) a lie, one of the numerous real world consequences of which is that it pushes the burden of responsibility for information-sharing about sex onto trans people. Who, in the nicest possible way, seem to have above average rates of mental health co-morbidities, high levels of denial/reluctance to acknowledge their sexed bodies and above-average difficulty in seeking care. This is not in their interests, and its also unfair on individual clinicians, who may be providing inappropriate care because they are being kept in the dark about their patient's real sex.
It doesn't really matter that this is what the representatives of trans people lobbied for. Medics should have been the grown-ups in the room who were tough enough to say 'no, because this will create real harms', or to insist on an appropriate workaround (such as retaining sex information but adding information about transgender status, or having specialist registers of transgender patients).
I get that medics are in an difficult position because they created/fuelled the idea that administratively erasing all trace of the past is part of the therapy for gender dysphoria. But they have only magnified trans people's problems by caving to the activism where health records are concerned.