Do your friends have a good bible teaching church they belong to? I go to an assembly of God christian church, and this past Easter Sunday their were many testimonies of people in our church who were healed of illnesses like cancerous tumors, and set free of addictions like smoking for 20 years. There was not a dry eye in the house as these people were telling the congregation their stories.
Prayer is very powerful, and having your whole church pray for you, while you keep the belief that you can be healed, often leads to miracles! I have already prayed for your friends, but they need to believe that Jesus still heals those who believe if only they have faith.