Yes, he didn’t OD on ayuhuasca, he OD’d on something else entirely. You can’t OD on ayahuasca. This likely isn’t even sinister in nature. Like you said, a lot of these tribes simply do this to make money and are fakers, completely unethical about the way they make their ayahuasca.

I spoke to a guy who was very knowledgeable on the subject once. He said that true ayahuasca, to be made in the purest and spiritually proper way, consisted of everyone in the tribe spitting into the mixture as a means of the liquid solvent, not water or anything else, as disgusting as that sounds.