This is going to sound awfully morbid, but how much time do you think she has left? I don’t think her results are even slightly optimistic… makes me wonder whether she needs to get off socials in such a very hard-line way (ads, smiley persona) and focus more on her family and the people she loves. At times I wonder if even the ads are escapism for her. Makes her feel like she’s doing something outside of “being cancer”.
When my sister got her diagnosis she went into a sort of bubble of denial, which she never really came out of. Even towards the end. I think that's fine - it's one way of dealing with it. My husband kept saying she wasn't ever really "facing it" but to be honest, what does it matter? For some of us really facing it might mean just drowning in depression. My sister wasn't a disney-princess-on-speed though, it was more that she just determinedly focused on any positives and sometimes didn't seem to hear what the doctors were really saying (I hope that makes sense, not enough coffee yet!)
I dip in and out of this thread. I think it's totally fine to be annoyed by someone's persona, or the grabby selling selling/begging go-fund-me stuff, but how someone deals with their terminal diagnosis and what they choose to put out there in the World I think whatever is helping them. The monetising cancer thing bothers me. I feel that it's taking money off folk who most often have v. little themselves (probably less than the person asking). Folk can say, "well, no one forces them to give money or buy things" but it's not that simple, as there's emotional manipulation at play.
I also follow Limitless Em on Insta and IMO she's v. honest about her emotions and mental state and possibly more in touch with the reality of her situation, but then she gets messages telling her she's being depressing and miserable and there seems to be pressure and expectation that you'll "snap out of it". So you can't win really. I used to work with someone v. like Nicky, who did my head in (think sharing an office with a cheerleader!). You felt they were never really being honest. I've no idea what's going on psychologically with that sort of person.
Your original question though, she's on a v. similar path to my sister and you're right, sadly. I do think we live in a v. strange world now, where comments and validation from strangers mean far more to people than they should do. I guess if that lifts her up in some way though, then whatever helps get you through. Increasingly I feel like I'm part of an older generation who sees it all as a bit shallow and meaningless. People following you online don't really love you and certainly won't grieve for you, in spite of what they might say. I'm thinking like you and I wouldn't want to spend what energy I had on social media at such a time.
I couldn't look after him though as his was sudden. I am a funeral director so she is at our funeral home which brings me such comfort 
