My father did something a little similar; when he got older he had to take meds where he could not drink but he wouldn't give up drinking right away; I remember one night that was extremely scary where he was driving and almost having accidents right and left. It must have gotten through to him and/or my stepmother must have intervened because he stopped drinking at all after that.

Think about your own body and how it works and how you think you can/cannot do certain things? I'm getting older now and my body is doing things it didn't use to and just figuring out things, that I'm not "as strong" (how strong was I?) or fast or can't stand or walk for as long a period time; there are so many different possibilities as to "why", could be that your father knew if he did or ate X, he was more likely to have a seizure or if he was stressed or something and he was learning his way around, "Oh, I'm feeling stressed now so I should not drive". That he told you he had a toothache was probably to protect you, so you would not be as frightened? It maybe would/would not happen again but he couldn't know and didn't want others, who would know less than even he, concerned and messing with it, pestering him, etc.? You know how you sometimes just want to deal with your own things you are familiar and comfortable with yourself and not have a big issue made of them?