It's not *really* bad. I had two beers yesterday after a very long period of greentea-totalling and I felt smarter than ever. No remaining effects whatsoever on the next day. Just the same mild headache I've been having for months now.

I think you're being paranoid. The negligible amount of alcohol in your food is hardly going to have any effect.
Of course, theoretically, it could be somewhat worse for you depending on your particular health condition, but unless her cooking actually makes you feel worse, I wouldn't worry about it. (Or maybe not even then if you're mom is one of those women who tend to get very self-conscious about their cooking )

Interestingly enough, there's even some research that suggests alcohol in the blood at the time of a traumatic brain injury may mitigate the negative effects of the trauma. (On the other hand, it probably significantly increases the risk of a head trauma ocurring in the first place)