relocating for job

I have always been the responsible one in the house. I am 27 female. I am living in my home, working from there.. but soon my boss will ask me to come to my work city permanently. I cant leave my mom alone. My dad is not a really nice guy. The moment i shift he will just shift in the room where mum and i sleep now.. and she will be forced to do his every work.. he uses joint pain and the fact that he is physically disabled as an excuse to trouble my mother. I knw people must be thinking i am a monster but i cannot explain properly why i am saying all this.
It is just that i cannot leave my mother alone with him. But i cant take her with me too because we have a dog too. We cant take the dog. Moving will be a drastic change for mum too. She wouldnt like outer ring road area and the whole crowded city. I am not sure what to do.. till the time i am at home i was sort of protecting my mother but now i am not sure what to do.