Possibly. The Child Status Protection Act freezes a child's age for part of the process, generally by subtracting petition processing time, but it does not stop the clock entirely. Ask for the calculation before filing.
Calculate the protected age instead of hoping
Hypothetical example: the couple's son turns 20 next spring and the family expects the process to take several years. Under the Child Status Protection Act, the child's age for immigration purposes is reduced by the time the investor petition was pending, provided the child seeks to acquire status within the required period after a visa becomes available. Whether that protection is enough depends on how long the petition takes and whether a visa is immediately available for the category on the date the family can act; the visa bulletin governs availability. The realistic step is to file promptly, keep the son unmarried, since marriage ends derivative eligibility, and ask for a written age calculation at each milestone. If the numbers do not work, the son will need his own route, such as study, and the family should know that before committing capital rather than after. The spouse's derivative status is not affected by age.
Hypothetical example: an investor in an electric-ferry project has an unmarried 20-year-old daughter who is considering a wedding next year. The family must decide whether she will remain eligible as a derivative through the immigrant stage, because marriage ends that basis even before age is calculated. Obtain a written Child Status Protection Act calculation when visa availability and petition timing can be assessed, and discuss an independent route if the margin is narrow. An opening file audit should assemble a family timeline with birthdays, expected petition steps, and evidence of each relationship. Birth and marriage records settle those facts. The most damaging error is treating a child as automatically protected without checking visa availability, the petition's pending time, and the required action after a visa becomes available.