How do you get a visa in India to come to the United States?

My uncle and his family wants to come visit us in the United States, but every time they go to Mumbai to get Visa they get rejected? They have clean records and everything. They are only coming here as tourists and then going back but the Indian government is still not giving them visas.

What can they do?

How long is a work visa good for AFTER you leave the company?

Hi… If I am in India on a work visa and I quit in September but my Visa is good until November, how long can I stay? I need a few weeks to arrange things before I go. Thanks! If you can point me to a source that gives in writing the answer to this that would be a big help. Thanks!