The official programme materials are the source for family terms. Rules from other categories, including derivative provisions and work authorization, should not be assumed to apply here.
Do not reason by analogy from other routes
Other categories have settled family provisions, and it is tempting to carry them across: a spouse and unmarried children under twenty-one as derivatives, dependants permitted to study, work authorization available in some statuses and not others. Those rules belong to the categories that contain them and do not migrate. For this framework, read the official programme page and FAQ at the time the decision is being made, follow what they say about family members, and treat silence as an open question rather than an answer. Because a household decision usually involves schooling, employment and timing for several people, write down which of those questions the official material actually answers and which remain unresolved.
A household should distinguish the applicant’s proposed payment from each person’s separate immigration and relationship facts. Collect civil documents and passports, then ask which family members could derive status under the underlying route, if one exists. Do not promise that a parent’s payment automatically includes a spouse or child. Hypothetical example: a rare-book conservator is told that adult children are “included”; the governing family definition, not the sales message, determines who can be considered.
Ask for the precise legal category claimed for each relative, since a shared address, financial support, or family expectation does not itself establish derivative treatment.