ACA - Obamacare

I recently heard a story of someone who have health insurance then lost it because of Obamacare. This individual didn't have insurance for 3 years but was finally eligible for Medicare. Once he had Medicare he went to his doctor and found out that he was terminally ill. He died recently. The story goes that if the illness had been caught early on he may not have died. That's pretty much the story. I tend not to believe the story as there are no details as to exactly how he lost his insurance, what insurance he had or if the insurance was through an employer. Therefore I'm asking anyone here, could this have happened? If it could have, exactly how could it have happened and were there options this person could have taken that might have saved his life? Please only serious replies. Thank you.