Female Daughter Custody

My Husband is delivery executive and not working properly oe not earning . my child is Type 1 Diabetes patient my sister bear her all medical and sometimes education expense as well. I being mother take care of her as well. i earn less so i take help of my sister though my inlaws are financially stable they dont help me for my daughter or their grand daughter, but my daughters monthly medical expense is done by my sister without any miss. Recently because of my husband gutka chewing he is diagnosed and undergoing cancer treatment , he has got toxic so i started staying with my sister and mother. Now he is forcing me to live with him to take care of him. His parents denied paying for operation in private as his cancer was increasing and went to stage 4 from stage 2. my sister got emotional and did his operation and everything. I took care of him in hopsital still now he again started smoking wihtin one month. GEtting rude and toxic. My sister took a loan and did his operation still he is abusing my sister for my sole decision of not staying with him and giving me threat of suicide and taking away my daughter from him. I also allow him to chat with our daughter on phone and meet him sometimes but my daughter feels scared of him because of his toxic nature. he is not working and his cancer treament of fruther therapy is done at his parents place, Is there any chance of my daughter custody to go with his father if i file a complaint ./ My daugher is 11 year old