TD status lasts as long as her TN and ends when it ends, when a child turns 21 or marries, or when the marriage ends. TD permits study but never employment.
Derivative status borrows the principal’s clock
The spouse and unmarried children under 21 of a TN professional are admitted in TD status for the same period as the principal, and their status is renewed with hers. It ends when hers ends, whether by expiry, by termination of her employment or by a refused renewal, and each child’s TD ends on the twenty-first birthday or on marriage. TD carries no employment authorization: in the hypothetical, her husband, a self-employed cabinetmaker in La Pêche, cannot build furniture for sale from the U.S.
home, take a job with a U.S. shop or perform work for Canadian customers while physically in the United States, since the prohibition attaches to working rather than to the source of payment. If he wants to work he must qualify in his own right, for example under E-2 if he invests in a U.S.
workshop; cabinetmaking is not a listed TN profession. Canadian citizen dependants are visa-exempt; a dependant of another nationality needs a TD visa. Their daughter, now 17, has four years of TD before she needs a student or other status.