I have a brother who has cirrohsis, hepatitis C and just got pneumonia he is a drug IV user and drinks and smokes is this very bad?

Yes. Your brother has many medical co-morbidities that will make almost any medical problem in him worse and more difficult to treat. He needs to be under the care of a doctor, closely.
The Addict Brain. I do not like to use the word 'bad' or 'good' when it comes to our health choices. Your brother is in trouble..And may not be long for this life. His addict brain may see this as the only option. The disease of addiction tells the brain that death is desirable and often that the addict is worthless...So 'why care'?. I have seen many miracles of recovery. I will pray for your brother.
Yes, very. Your brother is at serious risk for an early death. Hep c and cirrhosis can lead (and often do) to fatal liver failure. They can also cause liver cancer, usually fatal as well. Alcohol is a liver toxin; mist of us who only drink a little have no problems with it but someone with a damaged liver handles it less well. I've drug abuse can kill many different ways: infections including aids.