Travel to India on AP (combo card), is re-entry to US possible if GC arrives while in India?

[lcdc2011]

My sister filed for my Mom's green card, my Mom received the combo card that is an EAD and states at the bottom "SERVES AS I-512 ADVANCE PAROLE". Though she hasn't received the GC yet, we heard back that she does not need an interview. We have no idea how long it will take for the GC.

1. She needs to travel to India for some personal work and we anticipate she will be there for around 3-4 months. Will she be able to re-enter the US with the EAD/AP combo card?
   
2. What if her green card arrives while she is in India? Should we just keep it here with us?
   
3. What documents will she need to show at the port of entry?
   
4. If for some reason her stay in India get extended, what is the maximum time she can stay outside the US?
   

Thank you in advance, your response is greatly appreciated.

[pontevecchio]

1. Yes 2. Yes, she should inform them of that fact when she returns. 3. Her EAD/AP . 4. I do not think she should spend more than 4 months back home, maximum 6. She should be getting the GC any day. Stays more than 6 months may need to be explained and may impact the GC.