Sorry to hear about your friend - RIP.
I have tried a lot of different drugs - everything except opiods - and I've never felt any sort of addiction to them. My health was always more important to me than continuing to trip or stay 'up'.
However, after knowing opiod addicts, hearing them speak, and witnessing what their withdrawal is like, I absolutely would never fuck with opiods.
I helped sit with somebody for some days while they went cold turkey. We had him high as a kite on ridiculous amounts of cannabis oil the whole time but it was still scary to see.