I am angry with my friend

She's not so much my friend as a good friend of several of my friends, but we share an orbit and I care about her. Last week she dropped out of sight. She stopped answering her phone; she stopped answering emails; she stopped posting on Facebook.
She went dark. I wouldn't have thought anything about that because when I'm busy, I don't tweet or update or post either. But here's the thing. The last status update she left on Facebook before pulling the plug was a stark, two-word message:  Goodbye everybody.
A frantic Facebook-fueled search ensued with people sharing information--where they last saw her, where she might have gone, who she might be with. Her sisters were all contacted and it was clear they had no idea where their little sister was.
They posted pleas for their sister to call them. Their kids posted pleas for their aunt to get in touch. No response. Radio silence. And the clock was ticking. People drove up and down streets looking for her car. People contacted a coffee shop where she was known to hang out. There was talk of posters and flyers and news stories on patch.com. (My over-burdened  NoHoNoir editor was ready to step up with an article, even though he is insanely busy.)

Instant messages and direct messages and off-line communications flew back and forth. One of the missing woman's friends reactivated his Facebook account just so he could follow events. And then on Sunday, word came that she had been found and was "in care."  Thank God, we all thought and that was the general tenor of the comments on her Facebook page.  Now today, the woman is back on Facebook, posting updates that are mostly mea culpas.
No mention of where she's been or what she was doing or even an allusion to being 'in care."
And yes, I KNOW IT'S NONE OF MY BUSINESS.  I do.  But here's the thing. Last time she had one of these meltdowns, I was the one who took her to the hospital. I was the one who sat in the waiting room while she had a psych eval. She wasn't admitted at that time because the doctor didn't think she was in danger of harming herself.
Define "in danger."
When I arrived that day with one of her other friends, she was close to catatonic, in the grip of a paranoid delusion. And even though thehospital visit was a "wake up" call to her, it didn't really change her behavior. And the delusions got worse.  Her friends contacted her family, who live on the other coast, and described what was going on and begged for help.
And meanwhile, our friend slipped further and further away.
She lost her job.
She lost her home.
She was offered rooms and couches and sanctuaries but none of them were in the city where she wanted to live, so she moved her posssessions into her car and went mobile.
And so frustration set in.
And at that point, I began to distance myself.
Crazy scares me.
My little sister was mentally ill and all the love and support in the world could not save her from her shadows. The coincidence that my friend went missing on the fourth anniversary of my sister's death made it even harder. Because my sister attempted suicide several times before the universe finally called her bluff and let her slip away quietly one night.
So yeah, I know that much of my anger here has more to do with my own issues than my friend's problems. (Yes, it's all about me.) And I wish I could be one of the chirpy Facebook friends leaving messages of love and light with little hearts and stuff. But I can't. Because I am angry with her.
I know my friend is sick. I am glad she is safe. I just want her to get some meaningful help before she ends up a statistic and a bad memory. 
I thought she was dead. 
Thanks for listening to me vent. Normally I work these emotions out in fiction but today I'm just angry. I'll feel differently tomorrow. And in the meantime, where there's life there's hope.
As William Blake wrote:  "I was angry with my friend; I told my wrath, my wrath did end."