Great episode!

To answer your question, I'm afraid I would sound like a broken record. Can you do crazy things in a lucid dream? Sure, because you are modifying that reality. Our "apparent physical reality" is not hard and objective - the evidence for this is stronger than most anything else in science. Instead, reality is soft, malleable, programmable, subject to our conscious influence, and capable of any sort of anomaly that can exist in code. And, by code, I don't mean C++, but rather the cosmic code that runs our virtual reality.

I'm not sure he was possessed. I didn't see anywhere in the story where he said he felt possessed or where his behavior was like his grandfather's, but I may have missed that point. This is a total wild assed guess but I think it was his state of mind. I've noticed that when I am in a very heightened emotional state - very angry or very upset (or very under the influence) - electronics around me sometimes behave differently, like a phone or laptop will reset, or the touch screen responds differently, or I'll press a soft button and the app behaves as if I did something completely different. There have even been times where I experimented in this state and found that my phone was doing things that would normally require multiple keystrokes, or several levels of interaction (like menu levels) that were objectively impossible from the screen I was on. I just did a quick google on it and found an article about this here: https://www.liveabout.com/people-who-affect-electronics-weirdest-stories-2596556

There are also the reports of people (who claim to be psychic) physically affecting their environment; e.g. telekinesis.

So in this case, he was in such an incredibly emotionally heightened state because of all of the bad memories that were flooding back, that he was able to influence his environment in a much more profound way than making a phone app behave differently.

I also found this interesting article: https://www.psychologytoday.com/us/blog/long-fuse-big-bang/201509/telekinesis-making-things-move-your-mind-is-possible. Clearly, our consciousness can collapse probability wave functions through intent, aka the observer effect. What I hadn't really considered before finding that article, is the extent to which our consciousness can potentially change reality. If you think about how most of the particles of "matter" (really, information) out there are undefined, even in the room you are in, wouldn't it be possible for a powerful conscious state to collapse a whole lot of wavefunctions at once (e.g. water molecules)?

Good points, perhaps being "possessed with an evil spirit" was just a way of them attempting to explain what they didn't understand, my impression was that he was temporarily possessed in some way by his grandfather, perhaps partially(if that's even possible?). Emotional interference with electronics is new to me, very interesting. I've only had one strange incident regarding electronics about 15+ years ago I woke up in the morning and my window AC unit and desktop computer in my room turned off and back on at the same time. I thought possibly a power surge, but the strangest part was that my cellphone on my table next to my bed(which was not plugged into the charger) was completely frozen at that same moment, to the point where I had to take the battery out and put it back in to get it to work again. No other room in my house was effected, it was as if some type of electrical pulse came around me in a small radius. Another strange note, I noticed a small bump on the back of my head that morning shortly after. I got it checked out, doctor said he wasn't sure what it was, not a tumor, but would remove it if I liked. I left it. Still there too lol.

Back to the topic, I think I understand well what you mean by the particles of matter being undefined and with intent, becoming defined. Where I was originally going with this, my idea was our consciousness could be heightened by an outside influence, creating the potential for a more powerful intent to successfully collapse wavefunctions like you describe. Another consciousness somewhat merging, the measuring glass of consciousness becomes a little more full. As you are saying though, the outside influence may not be necessary, it may just come from within given the proper concentration(or rage).

Why did the cross burn him? Was this perhaps evidence of collective intent? For example those in the room believed with certain confidence that the cross would burn him, and it did so.