A neurologist blogs:
How do you tell someone they have a brain tumor, a malignant brain tumor? This isn't something I recall getting out of medical school, at least in the texts. Even in internship and residency what you got along these lines was a lot of run-of-the-mill examples of watching your attending go through this, mixed in with some that were callous, bad examples, and a few that were so heartfelt and touching that your eyes felt like they were welling up like the patient's and family's as the telling unfolded.
But I can't recall any of them ever discussing this, before or after. There were certainly the feelings of dread as we walked in bearing the bad news, the unpleasantness of seeing the reaction to the diagnosis, along with the various side effects -- disbelieving the diagnosis, anger, stupefaction. The clock seemed to stop, and there might as well have been nothing outside the room, or for a moment nothing outside the room mattered...
You have to have some sense of your own feelings, but mostly you must be vigilant to the signs of feelings of others, the signs that someone else is either tuned in or out. If you can't explain things in nonmedical terms, you don't understand them well enough yourself and you should have come better prepared. You also must know when to quit, when to pause to let the information sink in, when to quit for now and come back later.
I've had people thank me for telling them what they were going to die of. It's uncomfortable to be in that position. I know they're thanking me for my honesty, for spending time to explain, answer their questions. But it's hard to say, 'You're welcome' after being the bearer of bad news.