The COPD won’t have caused the heatstroke but it will have made her more susceptible to it.
This is the thing with underlying health conditions, people don’t always know they have them until it’s too late.
During COVID for instance there were reports of perfectly healthy people who had died from COVID, including one who was a 13 year old boy, which turned out had an underlying heart condition he didn’t know he had.
Anyone can get heatstroke, but one’s susseptability to it does change depending on your actual health at the time.
So although she believed she was healthy, she wasn’t, so it’s not the same as saying a perfectly healthy 50 something year old woman just collapsed from heatstroke so it could happen to anyone, it’s more the case that no-one knows they don’t have an underlying health condition, sometimes until something like this happens to them.
The current state of her health is because of the heatstroke, but the heatstroke may not have happened if she didn’t have the underlying health conditions that she does.
The undiagnosed underlying heart condition I had meant I was more likely to suffer significant consequences if I caught the flu. But when I caught the flu I didn’t know that. The flu damaged my heart valve and caused sepsis, but had I not had an underlying heart condition this likely wouldn’t have happened.
None of that is a criticism, and the tragedy of anyone dying from a serious condition is not reduced. But there were clearly contributing factors which, while they don’t need to be considered after the event because what’s happened has happened, but they do need to be considered when you’re putting out a message essentially saying we could any one of us just collapse in front of the television and have heatstroke with no other conditions. That’s just not accurate.