More than likely, people of my generation who have tried to contact service buddies years later have been told by someone on the other end of the line that the person has died.
Graciously, the person may also have told you that the buddy contracted some unusual disease or described some other circumstance that contributed to the buddy’s early death.
There wasn’t a green sedan with two immaculately dressed service members who walked to the door, tapped lightly and then, in a solemn, dignified manner, gave regrets to the heart-throbbing loved ones.