I'm so sorry. It sounds like there are both depression and control issues running through her head, which makes it impossible for her to follow your advice, and the more you push/suggest/arrange/etc., the more she insists on running the other way, because getting help would require admitting that you were right. So I would second the suggestion for a therapist for YOU, to help you navigate your own stress about this problem, and to help you learn what might be helpful and what might not be.
FWIW, depression is evil and insidious, because you feel "normal" the entire time, and you don't realize your perception is so warped until you come out of it. I have had a couple of bouts (one recent), and neither one was a big, "oh, woe is me, life is so awful" crying-jag kind of thing -- honestly, I never felt "bad" at all, ever. I just felt disconnected from everything. The world was grey, and everything was boring, and I just couldn't think of anything that sounded exciting enough to justify the effort required to go get my butt off the couch and do it. This is the best thing I have ever read that explains it:
http://hyperboleandahalf.blogspot.com/2013/05/depression-part-two.html. So I would do completely self-defeating things -- like go to work and putz on the internet literally all day -- knowing I was shooting myself in the foot, but unable to force myself to do the work. I started driving ridiculously fast, and it wasn't until later that I realized that the nerves/adrenaline that come with doing that were the only time I actually *felt* anything -- I was intentionally choosing stupid things, just to feel something.
The first time, I got very, very lucky: turns out it was a side-effect of a medical condition, and when I got that condition diagnosed and started medication to get my hormone levels back to normal, within three days, it was like the sun came out on my life again. And I looked back at the prior 6 months, and basically said, "oh, holy fuck, wtf was THAT?!" I didn't even realize I had been depressed until I was better!! And that experience was what saved me this time: again, I felt 100% completely normal -- but then my rational brain was able to look at my behavior, and think, hmmm, I like my job and yet am doing things that I know will get me fired; I'd like to live and yet am driving like a total maniac; there's something wrong, let's go to the doctor. Even then, it took me 3 months to care enough about it to follow through -- the thing about depression is that it is like a virus that wants to replicate itself, so your brain becomes extra good at coming up with excuses for why it's NOT depression ("it's just a really boring project") or why you don't have time to go to the doctor or whatever. It wasn't until I didn't even want to go out and do things with my family on the weekends -- my family, which has always been my sunny day no matter what -- that I was able to overcome the evil lady in my head, because I KNEW that was not me, and force myself to make the damn phone call to set up the appointment. But once again, as soon as I went on the meds, the cloud lifted, and I was able to see the past few months clearly. But without that prior experience, I wouldn't have had the knowledge to really "see" how not-me I had become, and the evil lady in my head would have been able to keep convincing me that I was the same person I'd always been, and that the way I was feeling/behaving just a rational response to some outside problem.
I know this is long, but the point of all of this is to try to explain why you cannot force someone who is depressed to get help -- who they are and what they are doing
feels 100% normal to them. And the more you push, the more ammo you are giving to the evil lady in their head -- oh, no, honey, it's not you, it's that crazy mother again, trying to control you and tell you what to do, you need to assert your independence and show her who's boss, don't go to that silly therapist, don't go to the doctor, you're just fiiiiiinnne. I think all you can do is just provide quiet support, without judgment (I know, as a mom, it's almost impossible to say anything without either intended or unintended judgment, right?). The message has to be "I'm here for you, I love you." I think the hardest question you can ask is something like "are you ok? you don't seem like you." If you need to push for something, don't push for therapy ("you're 'wrong' and need to be fixed"), push for a visit to a doctor (because in many cases, depression is biochemical, and you actually NEED medication to produce whatever your body isn't -- I had therapy a few times over the years, and it never fixed anything, but medication, whoa, poof, gone.).
FWIW, my brother has been dealing with anxiety/depression all of his life, and spent probably 20 of those years in a pushme-pullyou with his parents. It wasn't until he moved across the country and severed all normal communication that he had the space he needed to see a therapist and get on meds, and after many years of hard work, he now has a job and a car and appears to be back to functioning again. Watching him flounder, and seeing that every effort they made to help just backfired, was THE hardest thing my mom and stepdad ever went through. But part of parenting adult children is realizing that you can no longer fix everything for them, and that they are entitled to make their own decisions, no matter how stupid they are. I'm sorry.