The three men ingested whatever via however, and died outside in very cold weather, so all forensic evidence outside was perfectly preserved by the freezing weather. The police certainly got a search warrant and turned JW's house upside down looking for any evidence of drugs, drug manufacture, drug use, whatever. They would have searched the car(s) the three came in, and whatever of their personal belongings were in the house or outside with them, like coats, jackets, pockets, backpacks, cell phones.
JW has not been arrested or named a POI, so I'm assuming (MOO) there was nothing that incriminated him, but there was evidence that one or some of the three brought the drugs to the house. Who knows, they could have even bought the stuff over the internet.
Has this been addressed already? I did a cursory search on "adverse reactions to alcohol + fentanyl".
If the friends had been drinking beer all afternoon and into the night...and then ingested/smoked fentanyl, here's the thing:
alcohol and fentanyl are both potent depressants.
Health line.com, Sept. 23, 2023:
Understanding the Risks of Mixing Fentanyl and Alcohol
"When you combine depressants like alcohol and fentanyl, the effects of each drug are amplified, which can significantly increase the risk of overdose and even death."
I know it's incredibly hard for the families to process this horror, And yes, recreational use of illicit substances would/could have been a closely guarded secret from the parents, and possibly even spouses. But I hope they can realize that (MOO) this tragedy was the outcome of decisions on the part of their loved ones who just wanted to have a good time.