"Source?"
Knowledge and understanding of reality.
"The coroner said otherwise, that the cause of death was the drugs."
Your memory is bad. You were told on this thread that the coroner was unable to determine the cause of death. All the other claims are empty, because there's no data published to back them up. Only the lawyer put out some partial data and that inclded only 8mgs of morphine. The idea that 8mgs of morphine and a dose of versed is deadly and killed his ma is laughable.
"But, of course, he didn't have the benefit of your special knowledge. /sarc"
Yes I do have knowledge, but more importantly understanding. I think some other folks do to and in combination with a strong value for honesty would realize the most likely cause of death was the damage caused by being in those conditions.
Don't believe me? Contact one of those Vegas odds makers and get the odds for survival of a person after putting an 89+y/o, in critical condition, or a 61y/o 380 paralytic in a 110 degree, 100% humidity concrete box. 39 folks died in the hospital over that time, when the noramal was about one/week. Write a thread and see what other folks think about putting folks like that in a 110 degree, 100% humidity concrete box amounts to. I think the answer will definitely contain their estimation of the chance for survival.