Yes; his spouse and unmarried children under 21 enter in L-2 status for the same period, the spouse is employment-authorized incident to status, and the children may attend school but not work.
L-2 status follows the principal’s period
Dependants of an L-1B transferee are admitted in L-2 status and their period of stay tracks his. In the hypothetical, his wife manages bookings for a group of Val-des-Monts cottage owners; in L-2 status she may work in the United States for any employer or continue that business from the U.S. home, since her authorization is incident to her status rather than tied to an employer. Their daughters, aged 8 and 11, may enrol in school. The family’s status ends when his does, so if the petition is not extended their permission to remain ends with it; L-1B is limited to five years in total. Each dependant must prove the relationship with a marriage or birth certificate, translated where necessary, and must hold a passport establishing citizenship. Canadian citizen dependants do not need L-2 visa stamps; a dependant of another nationality needs an L-2 visa from a consulate first.
Before booking travel, compare the principal’s approval period with each family member’s passport expiry and assemble the civil certificates in the form required for entry. The I-94 admission record settles the duration actually granted at the border, not the family’s intended assignment date. Hypothetical example: a specialty paper-mill sensor maker transfers its systems expert while the expert’s partner will continue remote bookkeeping. The family should obtain status documents first and make independent work plans only after admission details are confirmed. A child approaching 21 needs a separate timeline early.