As to the why: bear with me here, this is kind of out there. I had gotten to the point with my mother where i felt like it was gonna be her or me. I absolutely could not stand to see her anymore. (This now also applies to her remaining sister.) I feel like i am just going to spin into a tornado.

Well guess what - the one who controls what i do is me. What if you had gone out of town while your sister visited? Instead of all the energy being put into this incident? They are JUST two different things to do. One takes taking responsibility. But only you can stop the tornado.

ETA - Yes, you risk ostracization. People wont understand. But thats not a reason for you to do (or not do) stuff. They wouldnt understand what you ARE doing. So your choice is equal. As Joey from Friends says, its a moo point - cows dont care what you do.