Yes, if he owns and directs it, the investment is substantial and at risk, and the business is more than marginal. Working alongside employees is permitted; being the only productive worker does not automatically fail E-2, but the enterprise must still have the present or future capacity to provide more than a minimal living or make a significant economic contribution.
Direction and a non-marginal enterprise separate an investor from a self-employed tradesperson
Hypothetical example: an East Hants electrician buys a U.S. company with two licensed electricians, an apprentice and an office administrator on payroll. He will estimate jobs, price contracts, hire, and hold the master licence the business operates under, while also working on larger installations. That describes development and direction of a real enterprise that employs U.S. workers. Contrast a purchase of a one-truck operation where the seller was the only worker and the buyer intends the same; the business may be real, but the evidence must still show present or future capacity to generate more than a minimal living or make a significant economic contribution, generally within five years. The licensing question runs in parallel: many states require a resident master or qualifying agent, and the immigration approval does not waive that. Confirm with the state board whether his Nova Scotia credential is recognised, and what examinations are required, before relying on the business operating under his own licence.
Hypothetical example: an East Hants mobile hearing-aid clinic owner buys a U.S. practice with two audiologists and a service coordinator. The first review should separate her business-control evidence from the state authority's licensing rules and from the payroll forecast. The purchase agreement, operating agreement, and staffing records show whether she will direct a genuine enterprise; a state board letter shows whether she may provide regulated care herself. If future revenue depends on services she is not yet licensed to perform, the plan needs another qualified professional.