Describe the actual activity and review authorization before it starts; unpaid does not automatically mean no work-permission issue. A qualifying L spouse may work incident to valid dependent status with appropriate spouse-specific I-94 evidence.
Assess the placement rather than its label
Clarify the duties and host organization. An unmarried child under 21 may qualify as an L dependant but does not receive the spouse’s employment authorization, so the same placement cannot be assumed permissible for a dependent child.
Dependent children do not acquire the spouse’s work permission, and family ownership does not remove the authorization question. A host organization often has its own written policy on unpaid participants, covering supervision, insurance, and liability, entirely apart from any immigration question raised by the family itself. Request that host organization's own written description of the actual placement before it starts, since its internal classification of the activity may differ from how the family originally assumed it would be treated by everyone involved. Compare that description carefully against the spouse's own status limitations rather than against the principal's separate work authorization, because the two are evaluated under genuinely different terms and different evidence. Ask clearly whether the host organization requires its own agreement or liability waiver, and keep a copy of that document together with the family's other placement records for later reference.