Not automatically. The official materials set out separate terms and charges for spouses and children, so each family member should be listed and the applicable charge confirmed. Children's eligibility depends on age and marital status under the immigrant rules that apply.
List the household and price each line
The program's published terms distinguish the principal applicant from dependants, and the family charges are stated separately from the principal gift. Before committing, write down each family member with date of birth, citizenship and marital status, and match each to the current official terms. A child approaching 21 raises the same age question as in any immigrant category, and the answer depends on the rules the program applies, not on the family's expectations.
A spouse's eligibility to work after arrival, and the treatment of a child who marries during processing, should be confirmed from the official text rather than assumed from EB-5 or L-2 practice. If a family member is not a Canadian citizen, note that separately, since admissibility review is individual. The total household cost is the sum of the lines, and it is not refundable in the way a business investment might be recovered.