I petitioned my mother and was approved for a green card. Our relationship has gone sour since she came to the US and is beyond repair. She has lived with me for almost 2 years now. Her presence has brought a lot of emotional and physical stress in me. I no longer want to continue my obligation (having sponsored her) to her. I would like her to go back to our country but she's conniving of returning here without my knowledge. I want to petition my brother and his family instead. Can her green card be revoked since I don't want to take full legal responsibility for her while she's here in the US? Please help. Thanks.