Answer:
I would say that the person who gained the cardiovascular disease is the person mostly at fault. You can say that work also played a part in the reason why you can't do to many physical exercises which is understandable, but work doesn't control how much you smoke or how you eat. You can still work normally without having burgers everyday. Even if you're stressed in work doesn't mean that you should resort to unhealthy habits that could have most definitely been avoided in the first place. So all in all I would say that the person who obtained the cardiovascular disease is at least 75% at fault while the work or the stress is at around 25% at fault.
_Ani H.
[Do not plagiarize] ありがとうございます (thank you)