TS: If the story is true, (Which I doubt) Lapin would not be the first person to be tripped up by the fallacy of equivocation.
You should doubt the story. It was written as a promotional book.
The analogy falls apart when you examine where the directive came from. In the first case (blood), the directive came from God/Bible. In the case of alcohol, the directive came from a doctor. A doctor does not equal God. (unless you are a narcisstic asshole like Lapin).
Also, the alcohol "will kill him" because the person had already overused alcohol. With blood, the patient had not created an internal environment that would result in death by taking it in - it was only a belief in death that the patient faced with the Bible directive, not an actuality.
Belief cannot be equated to knowledge. Belief is not necessary when knowledge exists.
The alcohol/blood analogy does not equate "like with like" - it puts knowledge up against belief...an apples and oranges argument.