Sorry to hear about your brother. I'll keep him in my prayers. My sister was also diagnosed with stomach cancer on July 4.
My friend told me that her nephew has cancer and his taking soursop tea. They family takes 15 leaves and boil it to make tea and have him drink it 2-3 times a day. The doctors told the family that the tumor is shrinking.
My sister can't eat or drink anything. So her friend makes the tea and wrap the boil leaves on her stomach. She said it help with the pain. Now she slowly drinking the tea.
I ordered the leaves on amazon
Soursop Leaves (Graviola Leaves)-(over 200 Leaves)-PURELIFE HERBS. My friend also told me about Huckleberry is also good.
Hope this help ;)