Investors & landlords

I don't believe the crux of the question is being answered here . . . is a (any) one-time capital gain(s) considered "household income" for ACA subsidized payment purposes?  I had a client (who was already receiving subsidized payments because they were unemployed) sell an antique car for a large capital gain.  More than 1/2 of the proceeds went to payoff a loan they had on the car, but the overall gain took them over the 400% poverty level.  This client (for the moment) is showing they have to pay back the entire $14k of subsidized insurance payments because they decided to sell this antique car because they couldn't afford the monthly payments.