So sorry to hear about your brother. I'm not sure if 4cm is considered large or not. I can tell you a bit about what my mom is going thru though.
They have not told us an actual letter/ number staging diagnosis for her. In my opinion, it doesn't really matter all that much. Anyway, in mid Jan. she was diagnosed with a tumor the "size of an orange" where her stomach and esph. meet. She was unable to swallow at that time. A few lymph nodes are affected, as well as a spot on her lung that they are unsure of what it is (might be mets EC or could be lung cancer or could be something else). ]
They started chemo and rad in early Feb. After 1/2 round of chemo and 4 rad treatments she began to swallow her saliva. She had now had 18 rounds of rad and is getting ready for her 2nd round of chemo next week. As of yesterday she had worked her way up to eating mashed potatoes! Considering where she started, that is great! Her last solid food was on Christmas day.
She is on a feeding tube, and has been since her dx in mid Jan. She would have starved to death without it. Hopefully soon she'll be off it. She had a love hate relationship with it. LOL
I wish your family the best of luck fighting this ugly beast. Please keep us posted.