This is so sad. I was unfamiliar with this whole dispute, but I've been a huge fan of the Doom 2016 soundtrack ever since that game was released. The music was absolutely essential to the game and it's amazing to me that they apparently didn't realize that and didn't treat the author as essential to the game development process.
I'm also worried that he apparently hasn't sued or settled yet. At least based on his story, it looks like he may have some amazing claims here, and any plaintiff-focused contract/IP firm worth its salt would be beating down his door to get this case. But some of his claims are likely state law claims that are subject to a statute of limitations that has either run at this point or is about to run, and settlement negotiations generally don't toll the statute of limitations. Get on it!
I'm also worried that he apparently hasn't sued or settled yet. At least based on his story, it looks like he may have some amazing claims here, and any plaintiff-focused contract/IP firm worth its salt would be beating down his door to get this case. But some of his claims are likely state law claims that are subject to a statute of limitations that has either run at this point or is about to run, and settlement negotiations generally don't toll the statute of limitations. Get on it!