Yes there can be an association with hepatitis c and non-Hodgkin’s lymphoma.
This is a community of patients so we really can’t answer such an in-depth question you best bet is to work with his care team. All I know is what I found on google from web md
How is B-cell non-Hodgkin's lymphoma associated with hepatitis C?
B-cell non-Hodgkin's lymphoma, a cancer of the lymph tissue, has also been associated with chronic hepatitis C virus. The cause is thought to be the excessive stimulation by the hepatitis C virus of B-lymphocytes, which results in the abnormal reproduction of the lymphocytes. Interestingly, treatment with interferon therapy has caused come cases of hepatitis C virus-associated low-grade (not very active) non-Hodgkin's lymphoma to go into remission. However, most individuals with hepatitis C virus-associated high-grade non-Hodgkin's lymphoma will require the usual anti-cancer therapies.
Wish I could be of more help best of luck to you both
Also from the American Cancer Society regarding non-Hodgkin’s lymphoma as related to the spleen
“Symptoms from lymphoma in the abdomen
Lymphomas that start or grow in the abdomen (belly) can cause swelling or pain in the abdomen. This could be from lymph nodes or organs such as the spleen or liver enlarging, but it can also be caused by the build-up of large amounts of fluid.
An enlarged spleen might press on the stomach, which can cause a loss of appetite and feeling full after only a small meal.
Lymphomas in the stomach or intestines can cause abdominal pain, nausea, or vomiting.”