My parents are here from India on B1/B2 visa. Their passport has now expired. The six month stay period will end in mid August.

The rule of thumb is that you cannot extend a B1 or B2 stay without a valid passport. Here are a couple of  suggestions: you can try to have your parents get extensions on their passports if possible before they expire in mid-August. Although USCIS would like to have persons file for extensions at least 15 days before expiration, it is perfectly fine to file an application even on the day of expiration. If you are not able to have your parents’ passports extended before the expiration date, they can file for B extension and explain that they are applying for passport extensions. Then when they receive them, they can try to submit copies of the extended passports to USCIS with copies of the receipts from USCIS. Good luck! Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.