1. If the divorce is a contested or by mutual consent then it is legally valid in India.
You do not have to validate the same in India after getting a divorce decree in US but restricted to the above two forms of divorce and not an exparte divorce.
2. If the marriage was dissolved by a contested or mutual consent decree of divorce then you dont need to validate the same in India nor you have to file a fresh petition in India.
3. If you plan to file divorce in India itself then you may give POA deed to your father to represent you during your absence in the court of law.
You can make yourself present during the time of chief and cross examination alone.
4. If it is a contested divorce it may take three to four years to gt disposed