Liver cancer stage 4, cirrhosis from hepatitis C and developed lung and spleen cancer, age is 70 can chemotherapy be useful?

Doubtful. But it never hurts to discuss this with an experienced oncologist (cancer doctor). Make sure, however, that you know the chances of response as well as the changes induced by the toxicity of the drugs, which may make you more miserable than the disease without changing your life-expectancy.
See below. May be in certain situtations; it depends on other medical problems particularly the state of liver function; discuss with your oncologist.