Drinking
alcohol is NOT fine for him. It is very dangerous.
Hepatitis C attacks the liver and so does
alcohol. Normally, the liver can handle alcohol in the body, but if it is under attack from Hepatitis C, you don't want to put his liver under any additional stress.
As far as precautions, avoid contact with his blood. Don't share razors, toothbrushes, nail clippers, or anything else that could have your blood on it. Cover any open wounds or sores with bandages.