Immigration status and repayment are independent. A delayed exit does not by itself affect a spouse's or child's derivative case, and conditional residence continues on its own terms. The practical effect is financial: school fees, housing and income planned around returned capital need another source if the exit slips.
Fund the household from somewhere else
Identify how the family will live during the years before any repayment, and whether a spouse expects to work — a question that needs its own assessment rather than an assumption. Record each dependent's birthdate and relationship early, because eligibility for a spouse and unmarried children under 21 is assessed on the facts and age protection is not automatic. Keep the investment ring-fenced from money the household needs.
Work out how the household will live during the years before any repayment, and write the answer down as a funding plan rather than an assumption. Keep the invested capital ring-fenced from money the family needs for school fees, housing, and ordinary costs, because a delayed exit is a financial event rather than an immigration one and does not by itself affect a derivative case. Record each dependent's date of birth and relationship early, since eligibility for a spouse and unmarried children under twenty-one is assessed on the facts and no age protection should be assumed.
Where a spouse expects to work, treat that as a separate question needing its own assessment rather than an inference from the principal's case.