Each accompanying spouse or unmarried child under twenty-one adds both a further processing fee and a further gift of one million United States dollars. A nineteen-year-old can be counted on those terms; a twenty-two-year-old is outside them and would need an independent basis, whether through study, employment or another route.
Two children, two different answers
Families rarely expect the answer to differ between siblings, and here it does, on a single date. The younger child can accompany the household as published, provided she is still unmarried and still under twenty-one when it matters, which is a question about the timeline rather than about today. The older child is simply not within the accompanying category and no additional payment changes that; his options are the ones available to any adult, and they should be examined on their own terms rather than folded into a family plan that cannot include him.
For the household as a whole, the arithmetic should be done person by person before any decision, because a figure quoted for one applicant is not a figure for a family. Where a household is close to an age boundary, the honest advice is often to establish the older child’s route first, since it is the harder problem.