How very heartbreaking. Sending you and your family prayers and good thoughts. From the article you posted, it seems you and many others will have countless wonderful memories to cherish.
I got a chill reading this.. As I child in my subdivision we once had a bad winter. Two men died of "heart attack" snow. the wet heavy kind. that is how I learned as a child for some odd reason, shoveling snow can induce heart issues. My dad was also a heart patient and my stepmom was the one who did the shoveling. There would be fights when he insisted on doing it himself. Then he got a snowblower for Christmas. My condolences to your family.
Edit: I had to google and found this.. so the snowblower wasnt a help either
Shoveling, even pushing a heavy snow blower, can cause sudden increase in blood pressure and heart rate, and the cold air can cause constriction of the blood vessel and decrease oxygen to the heart. All these work in concert to increase the work of the heart and trigger a potentially fatal heart attack.