Please help me understand what possibly might have caused my friends death; his father refused to do the autopsy.

I will refer to him as "E"

"E", some other friends and I, were hanging out just a couple of hours before he passed away. We smoked a few joints, but "E" took only a few tokes from the first joint and didn't smoke anymore. He kept nodding off, because, as he told us, hadn't slept for a day or two.

Then, we went for a walk and "E" was walking very, very, slow; literally like an 80 year old grandpa. He couldn't form two sentences, because kept forgetting what he was talking about. I also noticed that his pupils were very dilated.

We went home at around 1:15 AM(we met at around 10:30 PM). Next morning, my father woke me up and told me that "E" has passed away.

After "E's" death, I was shocked to find out that he was apparently abusing Tramadol(I never suspected this, because his uncle was a heroin addict, and he was always saying how he will never touch any opioids, because they ruin lives and was taking as example his uncle); and most probably OD'd(the nodding off).

AFAIK Tramadol causes Miosis(constriction of the pupil); not mydriasis(dilation of the pupil). And this is what I find conflicting here.

Also, "E" was occasionally using coke & speed, and more than occasionally weed & benzos.

So do you guys think it was just from the Tramadol, or he mixed it with something else?

We grew up together, and he was one of my closest friends. I really miss him.
R.I.P Date! Forever in my heart. <3

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