Well thats what its about. The course of the movie is a double entendre of the dudes fantasy of a life he wanted but could never have and he constantly thinks about killing himself
the end of the movie is him, at the very least, attempting to commit suicide by freezing to death in his truck. There's some point earlier in the movie that says something to that affect like 'it'd only take x amount of minutes to freeze to death' when they find the goats in the barn. He sits in his truck, starts hallucinating, and takes his clothes off like people in extreme hypothermia do.
Whether he actually leaves his truck and actually gets warm in the school is up for debate, but given the state of his truck in the end scene it seems pretty likely that he's dead in the buried truck.
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I promise that if the game stinks I will make a topic about how I hate it and you can all laugh at me - Mead on Fallout 76