B”H we still have a major talmid of the Chazon Ish who writes about this. THe Shevet Halevi who learned by the Chazon Ish for over twenty years. He writes in vol 10 chapter 13 that the Chazon Ish got all of his medical knowledge from his learning Torah and this is something special that is given from above, just like the Ramban and other. He also adds that the Chazon Ish had a ??? for these types of things. He adds that he was correct about 90% of the time.
May this be a Zechus for the Shevet Halevi and may Shmuel ben Rochel have a complete Refua Shleima.