I know it's really difficult to see that happen. I've been where you are, and where SHE is.
I admit that when I relapsed, I wondered why no one said anything. Not saying they owed it to me, or that it was their responsibility, but I did wonder. Like...do they not care? did I not really have a problem? Are they blind? Have I fallen into a parallel universe?
but I also have a friend who (I think) is in serious denial about her own drinking, and I don't say anything to her about her own drinking...because I know she will get her hackles up and tell me she is NOT like me. So when I speak of drinking/not drinking/recovery/relapse...I only speak about myself. She can take it or leave it or mock it if she cares to.
I have learned I have to take total and ultimate responsibility for my sobriety, no matter what anyone else, thinks, says or how they behave. but it does help when I get a little boost, show of concern, or they let me know they notice how I'm doing.