As a general matter, another party cannot use their own failure such as a failure to research the legal requirements to run this business, or his failure to obtain a license, as grounds to cancel or terminate a contract; only the other party's acts or omissions would allow that not his own. That said IF there is a written contract which states that you will maintain your license and allow him to use it, if in that case you cancel your license or otherwise deny him use, that would be a breach by you, and enable him to terminate the agreement. And if the contract specifically said he could use your license but doing so is illegal, then this was a contract to violate the law and contracts to do something illegal are void. The issue then is whether the contract says he could use your license, in which case it would be void or could be terminated; or if the contract was silent about the issue of the license, in which case the consequences of his failure to have his own license are on him and the contract is valid.