25:08 lol no fucking way this dude did any meaningful de-compiling. You're just throwing around big words Clay. So you decompiled every file you could find? I'm assuming that's hyperbole, but what did you decompile? With what decompiler? Looking for what? Are you confident you understood what you were looking at given that you aren't even a dev, let alone a reverse engineer? Sure, Java is easier to meaningfully decompile than native binaries, but that's still seems very "misinformative", as you would say.
My interpretation of his terminology is: "plugin" = resourcepack or datapack, "mod" = server-side or client-side mod. It's worth pointing out that you can do a lot with the first category. In particular, datapacks can use the Minecraft command language which is quite powerful.
https://youtu.be/GLJMnJxec7M?t=2665
49:35 second decompilation claim, now he's a Java developer. What's "the Java decompiler" btw? jad? CFR? There's no first party decompiler, only a disassembler... To be fair, maybe he just thinks his decompiler is the only one, idk.
Conveniently enough, he has all the excuses to not send the investigators a copy of his super seekrit mod. Not enough to nail him to the cross because it could genuinely happen in good faith though.
The rest of the story (3 months of guilt, tunnel vision) seems somewhat believable, I don't know.