My favourite real life crime show is Cold Justice and Torey Adamcik was actually a 'suspect' in one of the cases they worked on. A woman called Nori Jones was murdered in Pocatello, two years before Cassie Jo Stoddart was killed, and her house backed on to Torey Adamcik's parent's house. They actually went to the prison to interview him on the show (he appeared) and also talked to Brian Draper on the phone. I think the strangest/saddest thing, (I can't decide which) and obviously I don't know if this came out in the Disney+ show you watched, is that they don't talk to each other anymore and haven't for a long time. I found a documentary afterwards they'd both taken part in, not long after their convictions IIRC - the impression I was left with from that was that BD was very contrite about the crime but TA was not and his parents blamed BD for everything - basically, their son could do no wrong in their eyes. Sounds like this have shifted a lot since then from what you have said.
Anyway, if you want to watch the CJ episode, it's season 3, episode - Still of the Night. It's available on YouTube. It's my favourite ever episode and I have watched it more times than I care to admit. I won't give away the ending - just rest assured, I did a lot of stalking for ten years on this one

and I can pretty much answer anything you want to know!
Back to TA and BD - this is probably going to be controversial but I'm going to keep saying it anyway. Juveniles should
NEVER be given life without parole - it's unconscionable in my opinion - and the fact that this has been upheld in their case (yet probably would have been overturned in another state) is another travesty of the USA justice system.