On which Visa category has he been sent?
If it's H1 or L1, then obviously he would be on the rolls of the US entity AND under the purview of the US Taxes. So any Agreements he signed in India would NOT be valid.
If he has been sent on a Visitor or Business Visa, then obviously he would be still on the rolls of the Indian entity--and the Agreement you refer to would be VALID.
Having said that, usually any employee being sent on H1/L1 Visa is usually made to sign a similar/equivalent Agreement based on the US laws--to take care of eventualities while in USA.
31st December 2012 From India, Hyderabad