Visitor visa - re-entry for my mother-in-law

[prswarup]

hello,

My mother-in-law has a 10Yr multiple entry B2 VISA valid uptil 2014. She has left for India in September and we would like to have her back with us for my wife's delivery in March. What would be the necessary documents and letters (are there any formats for these letters??) that are required to be produced by her at the port of entry. Also, is there a limit on the number of months that she can be granted the I-94 for? the last time that she had visited her son she was granted a stay for 6 months.

Looking forward to your inputs.

Thanks in advance.
Swarup

[VisaChief001]

Multiple Entry visa holders can enter US anytime as long as they are not overstayed or violated their trip purpose. No docs will help in determining their duration of stay. Their intention is the factor considered by the POE Officer