10 year multiple entry B2 visa expiring. How to extend stay?

[lax100]

My mother is visiting the US and she arrived here on Jan 13, 2020. She is booked to go back on July 4, 2020. Her 10 year multiple entry B2 visa is expiring in August. In normal circumstances she would apply for another B2 visa with a US consulate in India. But right now with the Coronavirus situation, we are not so sure when the flights would resume. In this situation, if need be, how would one go about applying for another visitor visa from the US so that she can apply for an extension of stay with her current I94? I think one needs to file I539 for extending her stay. 
Thanks in advance! 

[pontevecchio]

The visa is ONLY an entry document/foil. The I94 keeps her legal and permits her to stay. She is allowed to apply for an EOS if needed. One can only get an US Visa stamp abroad.

[newacct]

US visas are only for entry and have no relevance to someone's stay in the US. You can enter the US on the day the visa expires and be admitted for months or years afterwards. She cannot get a visa from inside the US because if she is inside the US, she doesn't need to enter. For extension of status, she just needs to apply before her status expires, and have a valid passport. A visa is not relevant since she is not entering.

[MurthyIndia_Lawyer]

Hi!

We hope the COVID-19 situation improves  and your mother can travel as scheduled. However, if the flights have not resumed, then you will have to apply for an application to extend her stay in the U.S. (using Form I-539) with USCIS during the validity of I-94. 

Upon return to India, a B2 visa can be renewed within 365 days from the date of visa expiration of the visa, using the Interview Waiver Program.

[lax100]

Thank you all for the responses!