Hell, no. Punch-happy drunks kill people with their fists and feet all the time. Just last month a guy near here ended up in critical condition and in a coma because a drunk in a bar took a disliking to him, followed him out to the parking lot, and hit him *once*, causing him to fall and hit his head on a concrete parking berm. The poor s.o.b. is probably going to have permanent brain damage and spend months in rehab just because some dumb-ass was drunk and "punch-happy."
Being drunk is no excuse. When you physically attack someone, you get what's coming to you, up to and including getting your brains blown out.
Considering what you typed, considering how many times I’ve hit my head, or had it hit and been knocked out, I’m lucky I don’t suffer from anything specifically from that (though the people I know will vehemently argue different).
My father died two years ago today, less than four days after falling down in a parking lot and hitting his head on the pavement.