Fortunately your father's doctor were able to diagnose his disease before full blown, end-stage cirrhosis could set in. And, as you indicate, his chelating agent seems to be working well, so the advancing fibrosis should have stopped by eliminating the primary insult.
Keep in mind that the liver is amazingly robust and recuperative. If his liver is only in the early stages of cirrhosis, without the full blown architectural changes, things can get better.