Typically, 24 hours after the last coat is applied your floors should be dry enough to walk on and place furniture on. Even though the floors are dry, it will take the finish about 21 days to fully cure. Wait at least 10 days before you place any area rugs down.
Whether or not the liver damage caused as a result of alcoholic hepatitis can be reversed depends largely on the severity. As the hepatitis progresses it can lead to fibrosis, the forming of scar tissue in the liver. If this happens the damage may not be reversible depending upon how extensive it is.
Your friend does not have to worry. Hepatitis caused by alcohol abuse is not contagious. It is damage done to your liver by alcohol abuse. It is in a way similar to people who end up with cognitive problems from years of abusing drugs. You damage your own body, but not your partner's.