I really think you need to do what is best for you and not the family. Yes what I preach is tough but you are in a tough situation and should you decide to stay it is going to forever be a no win situation. Can you stage an intervention for your mom? Can you do some research on what resources are available that she can access in the area? Still, you need to look out for yourself.

There are resources for you. Talk to a guidance counsellor, talk to your family doctor.