This isn't bad news, it's just indicative of how much he's been through and how far he's come along since. Some of the doctors have used the word "miracle" in regard to Zack and a little more time to heal is a minor thing when looked at in that light.
Regarding his liver, he stopped taking an anti-anxiety drug called "neurontin" and his liver enzymes immediately dropped back to normal. Neurontin doesn't normally cause liver distress but he had just started taking it before his liver enzymes started to increase and it was the only change that coincided with it.
As always, thank you for keeping Zack in your thoughts!