Good luck @kitkatb with going back to work - it can be a bit scary but you'll fall in to it soon enough. And @afraser - maybe you need to find a project you can be involved in (once you've done some holidaying, of course). You don't sound the type to drift in retirement.
@zoffiel That's just shit. Is there a way that you can check in with your friend and let her know that you're there for her without crowding her? I guess that I'm thinking a note or email - something that communicates how much you care but gives her plenty of space to process it. I can understand your friend in that she may not want to discuss her diagnosis with anyone, even her closest friends. Talking can be just too hard. But she may appreciate knowing that you are there for her and that you can give her room to get her head around things.