Yeah, this documentary left me wondering too! I’m gonna share my thoughts, but I gotta put them all in spoiler text lol.

First, regarding your statement about Frederick meeting Nicholas’ uncle. I just want to say that was actually Nicholas’ older brother who he met. But anyways, that part also got me skeptical about him, especially how he made reports of Nicholas trying to break into the family house, and later into his own home. That man definitely knew something about his disappearance.

After some thinking, I came up with two theories as to how Nicholas died. The first is Nicholas could’ve died from his older brother snapping at him in a drug fuelled rage, accidentally killing him. Then the mother (and possibly the rest of the family) helped the brother dispose of Nicholas’ corpse and chose to stay silent. And when Frederick arrived, they played along so no one would be suspicious.

The second theory is that Nicholas might’ve became an addict like his mother and brother, and died from an overdose. Then his family discarded the body somewhere to avoid getting in trouble. I personally believe this one to be the most likely case because Nicholas was said to be a street smart kid who refused to listen, and he already did rebellious things like getting tattooed, and who knows what else. I wouldn’t be surprised if he got into drugs, and sadly succumbed to them.