The sibling who drove you everywhere before you had a license was saying “I love you” in gas money.

Those drives cost real money and real hours, and nobody called them affection at the time. They were framed as being made to take you, or as a condition of using the car, which is how a lot of family love travels. The accounting only becomes visible later, when you are the one with the keys and you work out what forty minutes each way actually costs.

You can say the thank you late, and it still works. Name a specific stretch of it, the year of practices or the airport runs. Then do the equivalent for somebody who cannot get anywhere yet.