Thank you for the welcome!
To address the laced with fentanyl comment just made about MDMA, yes that could be true, however, if he didn't take it alone, which I would guess he didn't, then the other people who would have taken it would have also taken fentanyl laced MDMA... Which is why it would be good to question them in the effects they had from it and whether anything was off. MDMA can also raise your body heat, so if he did get caught outside somehow he might have not wanted to wrap up warm and this could have had a more adverse effect on him and his body temp could have dropped dramatically without him even really realising it.
Although I think this is still the most likely possibility, especially if he took a concoction of drugs and alcohol, it is bizarre that they did not find him after the snow melted. As far as I can tell from maps, Sun Peaks is in a valley? So he had nowhere to really slide or fall down to.
Really hope they find him soon, the family sounds like they are making a lot of effort (as one would expect), and the mother seemed so determined after hearing her on the podcast. Hopefully they can find closure.