Actually, I do have a little sympathy ( and a lot of sympathy for aloha, before anyone jumps down my throat....)
It isn't difficult to be that stupid, i've done it and as a consequence am now religious about not driving when I'm drinking.
In my case, it was a works night out that I hadn't wanted to go on, in a crowded and noisy nightclub, where I felt left out and ignored. I'd had a few drinks, and wanted to leave, got outside and found my purse had been stolen, and I couldn't pay for a taxi.It was 2 am, I was due at work at 8, my car was nearby, the streets were empty, I didn't feel that drunk. It was stupid, but I drove home about 5 miles. Very slowly, and didn't hit anything. I know now that if the police had seen me driving that slowly, it would have been a giveaway. I would have lost my job, too.
I bet your dad is feeling rotten, starshaker. Yes, he deserves it, but drink does take away your powers of reasoning.