One of the many heartbreaking things about addiction is when someone's body gives out whilst they're still mentally trying to get sober and pursue recovery, even in the midst of periodic lapses.
Some people are in and out of rehabs for decades, seem to be a "lost cause" and then get and stay sober well into their 40s, 50s, 60s or even 70s. But for that to even have a chance of happening, the body has to have not given up on them. It's really the luck of the draw with regards to that. Some of us are lucky enough to stay alive long enough for one of our repeated attempts at recovery to finally stick, and for all that combined hard work over the years to come together. And for some of us, the body gives in even while the mind is still desperately fighting. It seems even more tragic when that happens, when that possibility of one day making it stick after so many years of hard work is simply ripped away because you were one of the unlucky ones.