The worst case scenario is death, and there are cases of exactly that documented everywhere. There are endless stories of injuries. The real question is why he chose not to do his homework before signing up for an injection of experimental poison, NOT why didn’t they tell me. They don’t care about you dude! Why weren’t you looking out for your own interests? Sorry he’s gone through this. Sorry that he didn’t take more of a custodial role over his own life.