@littlek,
Kris, I'm so sorry to read about this. It can be a nasty one.
I was diagnosed with
non-Hodgekin's lymphoma back in 1995. It was located in the exit of my stomach. I received 20 radiation treatments. Since then, I have had good checkups.
I was one of the few lucky ones as mine was caught earlier and completely by chance. My dictor was checking out my stomach for other reasones (via a scope) and found the suspicious area.
I had had no symptoms. From what I have read in the past, once some has them, the outcome is extremely uncertain.
Hoping for the best for your cousin.