Under the official framework the payment is described as a gift to the U.S. government plus a processing fee, not an investment, and the applicant should assume it is not returned. Ask the program directly whether any circumstance allows a refund and keep the written answer.
Treat the gift as spent and plan accordingly
The word gift is used deliberately in the official materials, and an applicant should read it literally: the money is given, not lent or invested. That distinguishes the Gold Card sharply from EB-5, where capital is placed at risk in a business and may be returned after the conditional period if the enterprise succeeds. It also means the veterinarian's practice sale proceeds, once given, are no longer available to fund a US practice purchase, a home or retirement.
Before paying, ask in writing whether the gift is refundable if the application is denied on admissibility, if the applicant withdraws, or if the program terms change, and keep the response. Confirm separately what the processing fee covers and whether it is charged per applicant. Tax treatment of a gift to a foreign government should be reviewed with a Canadian accountant, since the applicant remains a Canadian tax resident until she moves.
The sum of these answers, verified on the official page, is the real cost.