Yes. The employer's sponsorship establishes how the principal's application is funded, not whether a dependant qualifies. The spouse and the unmarried child under 21 are each considered in the initial application and must each be admissible and eligible for lawful permanent residence. Confirm the child's age and marital status against that category before filing.
Review three records, not one
Companies tend to screen the employee and stop there. Ask a qualified adviser to review the spouse's and the child's positions as well, including prior travel, any previous refusal, and documentation that may be held in another country. A problem on a dependant's record is a household problem the employer will hear about, and it is cheaper to identify it before US$45,000 in nonrefundable fees is committed.
Two points belong above that screening in any paper going to an approval committee. The payment runs from the applicant to the U.S. government and buys neither a classification nor relief from any ground of inadmissibility, so a company funding it is funding a process rather than an outcome for any of the three people involved.
And a determination must still be made under EB-1 or EB-2, subject to visa availability, so the substantive question is what the employee's own record could support. Confirm current terms and figures against official sources rather than an internal summary, since neither is fixed. Hypothetical example: a paper recommending sponsorship of a construction operations director sets out the three-person cost in detail and contains no view on which category the employee's record could support, and the second version reverses that emphasis and reaches a different recommendation.