Criminal Case against NRI

My friend is a permanent resident in the USA and is currently employed in the USA. He legally had right to a family property as part of a will written by the family head. The family head has passed away and he has been having issues with his siblings regarding the partition of family property. They are not willing to agree to the will. He is planning to have the will executed through court and claim possession of the property which legally belongs to him. But his siblings are threatening of filing a criminal complaint against him, stating that the will is forged, if he executes the will. He has concerns about his immigration and work in the USA if they file a criminal/forgery/cheating complaint against him. What would happen to his immigration status when a criminal case is registered against him in India. Are there chances for the complainants to move with the criminal case through the embassy and bring him back to India for any legal proceedings. How will this affect his career and immigration in the USA. Can you please help us regarding the above issue. Any help is much appreciated.