Please calm my anxiety down so I can take a breather from this worrying!!?

So when autopsy results comes back saying that person has died from natural causes due to the heart that may or may not be hereditary. 

Does this mean that person had heart problems,and the doctors didn't see it three months ago when he was possibly healthy as when the doctors thought he was fine on blood work and etc? 

I don't know this guy personal,but do know his wife. His wife found medical pieces like from an needle syringe underneath the couch which,she doesn't know how long it's been there. 

Since I heard the passing of the guy! My anxiety has been through the roof,but I want you please calm me down.