how to proceed in India against a Us green card holder

My husband is green card holder in USA i don't have green card. my son is 9 years old he is US citizen Iam staying in india for last 3 and half years with my son . he didnot contacted us from last 3 years. he sent mails asking me to file divorce in India and he will give me some compensation after completing the process. i want to file a case against him.some friends are advising me to come to USA and file case there as he is a green card holder. without going to USA can i file case in USA by hiring lawyers there.or is it ok to file case against him in India i have asked this question and i got answer like this "4) On his part, being a US Green Card Holder, he can file a petition for divorce in USA and the court may award him ex-parte verdict; based on principle of Res Judicata, this decree will be valid in India provided you do not challenge it here in India." So far i have not received any communication whether he has filed for divorce in USA or not .without my consent also can he get divorce in USA.Can i file any case in USA on behalf of my minor child who is a citizen of USA. If there is no chance of filing case in USA against him what options i have to proceed from India. Could you please explain.