B1 extension after I-130 approval

[montage9]

Hi,

My USC brother has filed I-130 application for my parents who are currently here on B1 visa for 6 months. Their I-130 has been approved. In the meanwhile, they would like to extend their stay for a few months because I am expecting a baby. Would their I-539 petition to extend stay on their current B1 visa be granted, given that they have an approved I-130?

I am aware that I-485 AOS can be done, but since my parents have commitments back in our home country, and the long wait involved for I-485 AOS, they would prefer to go back and wait for CP.

Also, does anybody have an idea on how long I-485 AOS takes these days for Vermont Service center?

Appreciate any insights you might have!

Thanks
-montage9

 

[Triple Citizen]

I-485 will initially go to Chicago and then to your local district office, not your local service center.

Also, does anybody have an idea on how long I-485 AOS takes these days for Vermont Service center?