Immigration Law Questions? Ask an Immigration Lawyer.
A foreign citizen visiting the U.S. on a visitor visa (usually a B1/B2 visa) is not permitted to work while in the U.S.
If this person is trying to get employment for a period of 10 weeks they can apply for a different visa type (there are several different types: https://travel.state.gov/content/visas/en/employment/temporary.html).
But the individual should not be working in the US if they only possess a visitor visa, if they are found to be working with this visa it can create problems for them in the future should they try to get future visas (of any type).