My mother has had depression for longer than I've known her. She has openly admitted to us that she would have killed herself long ago, if it weren't for the fact that she lost her mother to suicide and she doesn't want to do that to her own children. 

She was raised in an abusive household. Then in 2013 she lost her youngest child, my brother. She had never been to therapy or grief counseling. I know she was on medication at one point, but I am unsure if she still takes it.

I and my sisters are deeply worried for her. She rarely leaves the house. She sleeps past noon most days. She posts depressing and cryptic things on Facebook with no explanation. (Things like "I'm done" or "You did this to yourself." When we ask her what she means, she said "who knows. If the shoe fits.") When she drinks she talks about how terrible of a mother she is. How her life isn't what she thought it would be. 

My sister's and I want to sit down with our father and go over some ideas on how we can help her, but dad opposes the idea because he believes it will just make things worse. I don't want to ambush her intervention style, obviously that wouldn't be helpful. But I feel like we need to do something. 

I've been reading through the resources in the wiki, and we've been approaching this in all the ways it recommends. We listen to her, without judgment. We try to take her out and spend time in low stress environments. We don't criticize her, and we let her know how much she is valued and appreciated. We've encouraged her to find somewhere to volunteer, or to take up some sort of hobby. Anything to get her out of the house. (She retired 5 years ago). 

But it's not enough. 

I don't believe her life is in immediate danger, but it hurts to see her as this empty shell of a person who just spends all her time scrolling through her phone or sleeping. 

Please, any advice is welcome. Thank you Reddit.