B1/B2 Visa for Single Parent : H1B's Father

Hello Experts,

Kindly advise what all documents my father should carry for bio metric and consulate interview?
He has applied B1/B2 Visa: Business Visa/Medical Treatment. His purpose is to Visit me (I am H1B holder and in USA with my spouse and Kids).

Kindly provide comprehensive list of documents and example of acceptable document where ever required.

He is single parent (my mother is not surviving now) and my father is government retried employee. He is doing agriculture now a days in his own land in India.