Yes, that’s true. The AZ vaccine has been associated with loss of platlets and blood clots. (Though in all fairness there have been reports regarding the other Covid vaccines as well.)
However, in her case she may already have had antibodies against her platelets, making it much more risky to be vaccinated.
I understand your reluctance, considering both your parents (my condoleances). In your case I should definitely consult a hematologist before deciding to get vaccinated.
In a sane world you could hope to be treated (HCQ, Ivermectin, or some other anti-virals) early in the sickness, with very good likelihood of success if you ever had the misfortune to catch it, but these days... who knows.
I am almost 75 yrs old.
I have some risk factors.
On the other hand:
I have a decent dr.
I seem to have a decent immune system.
I rarely have to go out in the community.
I have a stash of several OTC things which should help.
I have Prayer.
Odds are I’ll be ok. If not - shrug.
Gotta go sometime or the other and I’ve had a great life.