Most Helpful Guy
Yes it is. However you have to go at some point and live your own life. That does not mean you do not love her, nor are for her, nor respect her.
That said, you may have to try to help her do some thing to cope. You probably can't surprise her with a move. You probably need to mae sure she knows how to contact you etc. But there is only so much you can do for her.
I am sorry. I know this is real stress...
Most Helpful Girl
You can have good communication with her and tell your sister to just keep an eye on your mother.