They do if the investment money passed through them or was jointly held, because the path must be traced whoever's name is on the account. Separately, an eligible spouse and unmarried children under 21 may seek status with the investor, and their inclusion is an eligibility question rather than a funding one.
Sort out ownership before the transfer
Agree which spouse is the petitioning investor and whose accounts will fund the capital, then keep the paperwork consistent with that decision. Marriage certificates, birth certificates and passports for everyone travelling should be gathered alongside the financial exhibits. Ask counsel early about a child nearing twenty-one, because age protection depends on the particular record.
Filing a petition does not authorise the family to work in or travel to the United States. Add one further division of labour to that decision. Where both spouses hold assets, keep the funding file and the family's civil documents on separate tracks with separate owners, because they move at different speeds and rely on different institutions.
A bank's archive team and a foreign civil registry have nothing in common except the ability to delay everything. Hypothetical example: an investor's household assigns the financial reconstruction to one spouse and the certificates, translations and passports to the other, with a shared index showing status, and the two workstreams proceed in parallel instead of one waiting behind the other for reasons nobody had noticed until the schedule slipped.