I've done just a little bit of research, and it looks like in Florida the prosecution would have to prove that Stallworth's drunkenness was the "proximate cause" of the death.... i.e. that Stallworth was drunk and that because he was drunk driving, the guy died. In other words, if a sober driver could not have avoided the accident/death, then Stallworth may not be charged with DUI Manslaughter.
So in Florida, the case law makes it look like it's not a strict lability offense like it is in Texas.
What does this mean? I think it means if the prosecutor doesn't think that it can prove that Stallworth's drunkenness was the cause, that he will likely be charged with lesser offense, like DUI.