Bad injury, skull fracture, brain bleed (similar to my experience). His longer-term outlook appears to be good: YouTuber has Rocket Launcher explode in their hands as devastating test goes awry – Dexerto
He appears in this updated video, post injury and recovery here: My RPG-7 Exploded On Me (in Slow Motion) – Ballistic High-Speed (youtube.com)
They appear to know what they were doing and this was an accident.
