My brother having b1/b2 visa earlier with his company now traveling to meet me

[ansarijaved07]

My brother having b1/b2 visa earlier with his company now traveling to meet me for a period of 3 weeks. His visa is still valid which going to expire in 2018.
Please guide me what documents requires for immigration.

[daggit]

He should carry documents that show his ties to home, the ties that prove he must return home once his 3 week visit is over.
And definitely a round-trip ticket.