covid 19 – Extend USA B2 Tourist Visa (for My Mother) stay under COVID19 + Flight ban situation


My Mother (63 yrs) is currently visiting me from India on B2 visa.
Now her I94 is valid till Sept 15 this year (visa is 10 yrs). Due to COVID19 India has flight ban imposed, and till now we dont have dates when the flights are going to resume. So I can see there is an option for requesting stay extension by filing a I539 with documents supported and I131 as I (son) will be her sponsor for stay and all expenses. We are looking for a stay request extension for max couple of months.
Now the questions are –

  1. How long it takes to get a decision (approval or rejection) in such cases ?
  2. What is the best time to file the extension request considering we have still 60+ days till the I94 expire in Sept 15.?
  3. If I file now, and we get rejection of extension of stay (before the current I94 expires), do my mother need to leave immediately or she can stay till the current I94 date (which is Sept 15)?
  4. If we get the rejection after I94 has expired (Sept 15), how many days she will have to leave the country? Does she accrues out of status in this case? and does the B2 visa (10 yrs validity) gets void as well?
  5. Last case – we file extension, we don’t get any decision quickly, but she leaves before getting the decision (approval or rejection, say she leaves at October end). In this case is she good in status, means no out of status and visa void?