Husband left home and no communication - we have a child 5 years old (american citizen)

Dear Sir - I am an Indian and working/single mother of an American kid. Currently, I live in the US and cannot travel back to India for any legal advice, simply because my son's passport has expired and my child's dad has refused to renew the passport. 7 months ago there was a fight between me and my husband and he walked out of the house. To cut short, the whole conversation: what can I do to ensure he doesn't take my child away from me because he has recorded me on camera screaming and swearing at him and has threatened to show to court/police and get custody of my child too. He started painting a picture that I am mentally instable. The truth of the story is that he has also been very disrespectful and has hurt me physically/emotionally/financially and socially but I do not have any recordings of his misconduct. Nor does my body has any marks of his brutality anymore. I am from a middle class family and do not wish to loose my child at any point in my life because my kid has been identified with autism. While my child stays with me, I support all the medical/therapy needs but because of the recordings I am very threatened that he will take my child away from me. Can I do anything legally to get my child's full custody? I want no money from my child's dad