Not automatically. The official page describes separate fees and gifts for each accompanying spouse and unmarried child under 21, and whether a sponsoring employer pays them is a term of the sponsorship agreement, not of the program. Each family member is also vetted individually.
Dependants carry their own price and their own vetting
The program's official description attaches its own processing fee and gift to each accompanying family member, so a sponsored employee's household is not included in the employer's headline commitment unless the agreement says so. Hypothetical example: a Shannon software developer with a spouse and two children under 21 must ask her employer whether it will cover three additional sets of charges, or whether those fall to her, and what the total is on the official page as it reads that day. Beyond cost, each family member undergoes the same vetting and admissibility review, so a spouse's prior immigration history or a child's medical record is its own issue.
A child who turns 21 before residence is granted may no longer be an eligible dependant; ask whether the program applies any age-protection rule and whether a payment already made for that child is affected. Compare with EB-5, where derivatives are included without additional capital, before agreeing that the framework fits the family.