I've seen Oxycodone used for chronic pain and Hydrocodone used for break through pain. Dying from an 'accidental' overdose is better than what lies ahead for most with COPD.
Yep. Art was a really smart guy. He had to have known those four drugs taken together could, and likely would, be fatal. Plus, meds come with instructions of not to mix, etc. With the constant pain he was in, getting worse all the time, struggling to breathe as Dannion said, he was suffering a slow, excruciating death. What was the point in continuing? It's not hard to imagine Art saying "That's enough" and taking that drug combo and going to sleep, knowing he would never wake up. And if that's what he did, I don't blame him at all.
Even if he hadn't died of the OD, how much longer did he really have in that condition? A few weeks? A few months, tops? He may have hit his 73rd birthday in June, maybe. He almost certainly wouldn't have lived out the year based on what we know about his condition. And his quality of life in that time leading to a natural death would have been shit and getting shittier. His doctor or doctors may have given a prognosis on his life expectancy at that point and he figured the hell with it, I'm checking out.
It's all speculation of course, but it doesn't make sense that a guy with Art's intelligence could make such a mistake with that witches brew of meds. Just my two cents.