The issue I have with the hypothermia theory is that it was only 42 degrees... that's not that cold. I understand that wind, rain and being without jacket could make 42 degrees colder. Maybe if he was outside the house for an extended period of time before heading home but even if the hypothermia had started to kick in... doesn't make sense for him to try walk.
He didn't have that far to walk and it wasn't that cold IMO. I grew up in a city similar to Boston weather. When I was 20, going to house parties / clubs without a jacket and in revealing clothing in 42 degree weather was normal.. no one wanted to carry a jacket... so we always "roughed it" as we called it. I remember countless nights walking home freezing my toosh off.
Also, I think for hypothermia to set in.. that means he had to be out there longer which would mean he got lost or disoriented. In order to explained getting disoriented, it's said he was "intoxicated" from the party. But IMO this actually counter acts that... IF he was intoxicated the "alcohol blanket" would have provided him warmth and hypothermia wouldn't have set in at least that quickly..... we always took shots before walking to bars in our mini skirts and skimpy tops to be warm for the walk.
If he grew up in this neighborhood, I think it would take a lot more than some drinks and weed to become lost. I still know my childhood neighborhood and the woods next to my house like the back of my hand... for him to have been seriously disoriented I think he would have had to been on some serious ****. And if he was on some serious ****... then no one at that party should or would have let him walk home.
The details are just too odd for me to simply write off as a lost kid and a tragic accident.