We can separate this into two parts: DrinkDrunk driving, and killing a person. But there are very different cases of “drink“drunk driving”. You can be the tiniest amount above the limit, or five times above the limit. You can be driving on your own in the most careful and focussed way possible, because you know about the higher risk and don’t want to be caught, or you are laughing and joking with your friends with the eyes not on the road, not recognising speed limits but showing off, uncapped to recognise riskier situations. The second one should be getting a harsher punishment.
Now tell me, which of the two is more likely to cause a lethal accident, or fail to prevent one? The second one of course. So if everything was done in a completely fair way, the killer should get the harsher drunk driving penalty in many cases. It is very hard to make a law perfectly fair, but harsher punishment for the killer will quite likely be fair.