you are not selfish nor a coward.you are a child who is scared to death at what your dad is going through. Draw your strenght from him. When you feel weak and afraid look at how hard he is fighting, When he is weak give him strenght from you by being supportive and understanding. There will be ups and downs but you must embrase each moment with love and courage. Allow yourself anger and saddness this is normal.Dont let cancer take over your life. Remember who your dad was before he had cancer and hold on to the hope he will beat this. God has a plan for all of us. Hang in there im sure your dad would want you to.