I watched it. I'm torn .. not sure, with only personal preference about what I'd like the truth to be to draw on.
I do not think he is lying .. I don't think a person can keep up the facade that long. I believe that he believes what he is saying whether it is true or not. I would say it is either true as delivered, or some of it is true and has been in some way reinforced / expanded on in such a way he is not aware of untruth in it.
A few years back a friend .. my hiking / bigfooting / hunting buddy .. spent a weekend with a volunteer group restoring trails into the area we research. They spike camped Saturday night, the organization that they were volunteering for brought in food, water, etc by pack train. He said that in the middle of the night, when he was in his tent, something was pressing down on his chest squeezing the air out of him. (Sound like Barton's account at all? :)) He said he told "it" that it was killing him and asked it to stop. It did. He could find no evidence of his experience the next morning. Though a bigfoot knower, he rationalizes that experience as sleep paralysis ... and maybe it was.
I see a few possibilities regarding his account.
1) It is a hoax. (As above, I do not think this is true.)
2) It is true, word for word. (I sure hope not ... but I do not have complete confidence, only wishful thinking.)
3) Something terrifying happened and was reinforced in a way that he believes the account he shared. That is where sleep paralysis might be the seed and his mind trying to cope with it, subconsciously constructing the rest of the story, could be the reinforcement. Without intending to assassinate his character, we have to consider substance abuse. Does not seem like he is a drinker but by his own words, he stayed absolutely plowed for the rest of his time there. Alcohol poisoning is a thing and at that level, alcohol can trigger hallucinations which can be connected to pre-existing intense fear.
There is no way for any of us to investigate to ferret out truth from this. We bring our preconceived notions of what is and what isn't, how people behave and how they don't, to the table and they color our interpretation of information presented to us. Sometimes right, sometimes wrong.
I think the wise thing is to keep it under consideration, like the Missing 411 accounts, in case the set up / precursor things seem to be happening to you so you can use what he did as a tool for getting yourself out of it, but do not overly dwell on it so that it ruins your time out there.
So, y' know, take it under advisement, but know there is no way to either validate or refute it based on anything other than pre-existing personal bias. ... and continue to be careful out there.
MIB