Did she ask you to cure this tumor? Did she ask you to post about it?
This is a common story in disability and chronic illness communities -- a partner gets so fixated on the illness they forget the human afflicted with it. The ill partner goes to the grave wishing their partner would stop fighting and start just spending their remaining time filling their lives with joy.
It leads to especially dark places when they don't succeed.
I wish him all the best, but don't lose sight of the human suffering the illness and what they want.