Please help, I don't know where to start

Hello, I was wondering if anyone could point me in a direction towards getting help for my mother, who suffers from anxiety and depression. She has never been treated for it, nor diagnosed with it. She is 68 years old. I'll have to tell you the whole story and I apologize in advance for how long it is. I just don't know where to start. My father died from a heroin overdose when I was 15(Feb 92), it was a really rough time and it was hard on her, but she was able to pick up the pieces and move on with her life. After he died, she met a man who she loved very much, (they were like soul mates) they spent about nine years together and he died a terrible slow death of lung cancer.(sept 01, funeral was on 9/11.Two weeks before he died, her mother passed away. Iam an only child and I have always been around for her, as we went through alot together, we became more like buddies than mother and son. My wife and I live in the same apartment building as her, but in separate apartments. Her fear is that I'll leave her. (which I would not do) but it's gotten to the point that I live so close to her, that I've enabled her over the years. (running errands, changing light bulbs. Etc so... Over the years, she had just shut herself in and refuses to get help or talk to anyone. Old friends, family members, she shut them all out. Just sits on the couch and literally rots away. About 4 years ago, she had a stroke and that's where it got really bad! The stroke itself was on the mild side, it left her with some weakness. She did the bare minimum physical therapy and didn't keep up on it. But now she had an excuse not to do anything! She got so weak from not doing anything physical, she started to wither away to nothing! Falling all the time, not being able to cook. Etc. This is just too much for me to handle and work and have my own life. Now as I type this, she is laying in a sub acute rehab, can't walk, can't feed herself. She is not even able to wipe herself! She also has c diff, which I think she contracted from not eating and weakening her immune system. She was also drinking straight brandy every night. Trying to numb the pain. Anyway... I know I can't let her come back to her apartment, it's just a breeding ground for negative thoughts, so we are looking at assisted living when she gets out. (hopefully she can get back to being able to do simple tasks (eating, showering etc. But what I need help with, is what got her here in the first place. How do you begin to treat this? Is it too late? I just want my mom to be happy again. Noone in this process gives much of a sh** about the depression side of it, they are just trying to make money and get her out of the system. Iam very scared and I need to hear from people who have gone through something similar or have any insight /guidance. I apologize for the bad punctuation and run ons. I have alot going on right now and I'm overwhelmed! Thank you so much for taking the time to read this. God bless!