No. Only the principal applicant's spouse and unmarried children under 21 are described as includable, each with their own gift and fee. A married adult daughter is not a derivative. In this example, her marriage to a US citizen and residence in Colorado do not by themselves establish her immigration status; her position must be confirmed independently of her parents.
Family inclusion runs downward and stops at 21
The official Gold Card framework permits the principal applicant's spouse and unmarried children under 21 to be included in the initial application, with a separate processing fee and gift for each included family member. Hypothetical example: the Lake Country couple's daughter is 38, married and living in Colorado, so she cannot be included as their derivative child. Any immigration status or sponsorship she has through her US-citizen spouse is separate from her parents' case.
What the couple are really asking is how to spend more time near her, and the answer may not require permanent residence at all. If the daughter is a US citizen or becomes one and is at least 21, she could in principle sponsor her parents as immediate relatives, a family route with no Gold Card gift and a different process. Compare one principal Gold Card case with an included spouse against family sponsorship or visits; do not assume both spouses must independently prove conventional EB-1 or EB-2 careers.