Does accupressure help in patients suffering from hep c and liver cirohsis if no allopathic treatment is possible?

Depends: It depends on what you are hoping to achieve. It will not cure it, however it may help reduce the symptoms causing distress in the patient, and has no significant down-side, so is reasonable to try. Acupuncture also of potential benefit.

Not a cure: You can use liver meridian to strengthen this tcm system but acupressure will not cure chirrosis or hepatitis c.