cookiepls

There's a lot of different reasons why people have nightmares. Stress, alcohol, some medicines, or even eating a large meal too close to bed time, etc. Your friend is experiencing the most common one - being chased. Usually by a male figure, but it can be animals or monsters too. It usually happens when there's anxiety about some unresolved issue. But the good news is, he doesn't even have to try and interpret his dreams. He can get rid of the nightmares while he's having one.

I've never heard of that religion (Gnosticism) but there are actually a number of other religions that use dreams. However, in the case of nightmares, everyone has had them, especially children. So it's unlikely that there's an evil spirit involved.

Have you ever lay in bed in the dark as a child, and felt some fear that if you put your foot on the floor, a monster would come out from under the bed and attack you? In real life, no matter how afraid you are, it simply won't happen. You know conciously that there aren't any monsters under the bed.
Not so in dreams. Whatever fear you during a dream usually comes true in that dream almost instantly. It's your subconcious bringing it about, because it doesn't know what's real and what's not.

The trick to stopping the nightmares is to face them. All my reccurring nightmares have stopped since I learned this technique. If your friend becomes semi-lucid during one of those dreams, his first reaction will be to wake himself up. That stops the dream right then, but it'll come back. Tell him to do a search using the words, lucid dreaming, to learn how to do that.

Anyway, tell him not to try to wake up. When the things start to come after him, he needs to turn around and say something very benign to them like, "Hi", or he could just smile at them, as long as he doesn't act or speak aggressivly. Facing a fear aggressively for some reason, just makes it become more aggressive. The point is, he should act the opposite of what he's feeling without trying to fight or threaten the monsters.

Here's what happens when you do that. You'll see what they look like, sometimes for the first time. Then they will immediately change into something else. They'll morph into something completely harmless. That nightmare will never return. This technique works so well, that I haven't had a recurring nightmare in over ten years.