This feels very unlike a game and more like the “other world” type of game similar to Mages are too OP, different setting, but familiar feeling. <- not criticism, I love stories like this.
Surely in a world where they can make a fully immersive VR System, there exists a way to cure his illness. Medical technology and techniques go hand-in-hand with other forms of technology as they evolve. I'm hoping he'll be healed or on the mend somehow. Possibly, since he'll become powerful in this game, he'll earn enough money for treatment. He likely didn't have enough before to be treated, or at least, that's all I can think of.
MILARCH