Most of my dead relatives died from smoking, so I'll pass on that. Drinking isn't as horrible for your throat, but it's still a bad idea to drink right around the time you want to do vocals, for two reasons. One is it fucks you up and two is you shouldn't practice or perform drunk because that's just pathetic. This is why it's fucking hilarious to watch studio diaries of Johan Hegg eating potato chips and drinking whiskey in the fucking recording booth, but when you growl like Johan you can do whatever the fuck you want. I sometimes drink warm water or tea before doing vocals but since I can't really predict when I'll be growling it's rarely worth the trouble.