Renewing Indian Passport in US while on a Visitor Visa

[kumsakthi]

My father has reached US on a visitor visa in April 2011 and his I91 is valid until Dec 2011. He also has an open ended ticket valid for 1 year.

I am thinking to start the Green card process for him, as I am an US citizen.

Also his Indian passport is expiring as of Dec 2011, can I extend it ASAP or when I can extend it and how it would affect his green card process? How long it will take to renew the passport?

Thanks!