request help for visitor visa b-2

[raj2014]

I am in US for last 2 years.

My Mother and Brother are applying for B-2 and their interview date is 19 Sep, 2013.

They are self sponsoring their visa.

My mother is widowed and house wife.

My brother is doing business for last 2 years.

 

1. What all documnets they should carry for interview?

2. In my invitation letter can I mention that I will take care of their house & food; and rest they are self sponsoring?

3. Apart from invitation letter from my side what all documents I need to send them?

 

Request you to please provide feedback.

 

Thanks & Regards