Only if they will genuinely develop and direct the business rather than collect its income. A hands-off ownership with an on-site manager making the decisions is closer to a passive investment, which does not qualify.
Direct the business or it is not yours for E-2 purposes
Hypothetical example: a Rothesay couple's purchase plan assumes the existing manager will continue to handle leasing, maintenance and collections while they visit for a few months a year. Treaty-investor status requires the investor to develop and direct the enterprise, ordinarily through majority ownership combined with operational control. Ownership alone, with the operations delegated entirely to an employee, may be treated as a passive investment.
The plan should be reworked so that one spouse takes the principal role: setting pricing, approving expenditures, supervising the manager, handling marketing and planning improvements, and being present in the United States for that purpose for most of the year rather than the winter. The manager can remain as staff, which helps with marginality. If the couple's real intention is to hold an income property and travel, E-2 is the wrong tool and they should be told so before the sale of the duplex.