No. The published terms extend to an accompanying spouse and unmarried children under twenty-one, each adding a further processing fee and a further gift of US$1,000,000. A child of twenty-two is outside that definition and needs an independent basis of his own.
Twenty-one is a boundary, not a guideline
Families expect adult children to be carried along, and immigration law almost never does that. Under the published terms Bertrand's wife and his nineteen-year-old daughter are accompanying family members, so the household faces three processing fees and three gifts rather than four. His son at twenty-two is not eligible as a derivative and would have to qualify on his own: a student status if he is enrolling, an employment-based route if his qualifications support one, or a family category later with its own waiting period.
The daughter raises a timing issue rather than an exclusion. She is inside the definition now and will not be after her twenty-first birthday, so the household's planning and the program's own processing timetable have to be read against that date. Because these terms are recent and may be refined, the current official statement of who counts as an accompanying family member should be checked at the time rather than taken from any secondary description, including this one.