What happened?

How did this happen? I am taking care of my mom. Well, my mom is now living in my house, with my grandmother. Mom takes great care of my grandmother but she can not seem to take care of herself. She is depressed. She cries all the time. This is not the mother I remember.
I remember my mom being strong in the face of anything. My mom and dad divorced when I was 11 or 12. We did have some crying sessions in the basement of the home we lived in, but then my mom got strong. She went to school to become a beautician and became a single working mom of four girls. I was the oldest my youngest sister was two. She was the strength that held us together. Then she met another man who would eventually became her husband my step dad. After a few years of marriage when it was evident my step dad was an alcoholic, my mom who had grown up with an alcoholic dad, did not want the same for us. She now became a single mom again this time of six children when she divorced my step dad. My grandfather, her dad, died during this time, mom was close to him. Just to prove how strong she was she did his hair for his funeral. She had always done it when he was alive and wanted it to be like it always had. I had moved out of the house by then but she sometimes worked two jobs to make sure my brothers and sisters were taken care. After a few years when my step dad wised up and got clean and sober they remarried. These were not easy years either. The mills closed down my step dad could not find work. The moved to Maine to start over and help him have a fresh start and new job. He had several jobs here and there, mom worked two jobs to keep the family going. May 17, 1990 ( I think that was the year), my step dad was training for a new job, he got sick and died suddenly of a massive heart attack. My mom was left alone again this time with two teen age boys who had just lost their father. She stuck it out until my brothers were both over 18 and could care for them selves then she came back home because my grandmother, her mother, was was going to have some kind of surgery. Mom stepped right in and became the care taker for my grandmother. I love my grandmother dearly but she was not always a nice woman. She was mean to my mom. After one such time when my grandmother had been in the hospital for some kind of surgery; we were going on a family reunion vacation, we had one every year. This year mom took care of it. The vacation was great we had a wonderful time, but mom was stressed to the max. She was taking care of my grandmother after her surgery, she made a mistake while figuring money for the vacation, and owed $1000.00. Instead of telling us and splitting it like we always did she hid it and put it on her credit card.
After the vacation, my son went home with mom they were going to have a great time. While unpacking the van, my mom became very confused. She did not know my sister, my son, was talking complete gibberish. She ended up in the hospital of what would be a long battle until my mom was diagnosed with blackout migraines. Since then she has had problems off and on, like were her and my grandmother were arguing, or something stressful would happen. Slowly we have ended up to where we are now. Last year was a doosey, around the first of the year my sister had a hysterectomy because of a hemorrhage, the same year in November we got a call that the same sister was rushed to the hospital they did not expect her to live she had an aneurysm burst in her brain. All they family rushed to her side and miraculously she recovered. PRAISE THE LORD!! The beginning of the next year my youngest brother had problems with alcohol which lead to violence and trouble with the police. My grandmother was forgetting more and more she would forget little things, then yell at my mom because she did not remember. Actually the more she forgot the nicer she has got.
In May my mom came down to SC for my son's wedding and when it was time to go home she had a total breakdown. I was supposed to take her and my grandmother to the airport, I got up early and went to mom's room and she was awake and crying she ask me if she could stay and not go home. I told her they could stay as long as she wanted, my husband confirmed this. After three months she decided to retire and move here. Everyone was OK with this until my grandmother stated she wanted to stay with my mom where she went. This led to an uproar in my aunt's family, my mom's sister. They could not take care of my grandmother themselves but did not want her moved away. We tried to tell them she needs total care and they did not want to hear it. They focused in on a trouble maker neighbor of my grandmother who told lies about who we had planned for a long time to take away my grandmother. Then barraded my mom with terrible emails and text messages telling her how she was never any good and it was terrible thing she was doing.
Which leads us to now. My mom at my house taking care of my grandmother crying everyother day. Asking "Did I do the right thing?" "Should I take her back there?" "What am I supposed to do now?"
My advise tonight was to STOP thinking about the past! FOCUS on the future! START taking baby steps to take back her life! Not to think of herself as anything but the wonderful person she is, the one who my grandmother chose to take care of her. The person my grandmother trust enough to take complete and total care of her. The one my grandmother says of her "I will go where ever she goes because she takes care of me."