The figurative language that can be found in the passage is a simile.
Explanation:
Figurative language refers to the use of words in a way that deviates from the conventional order and meaning in order to convey a complicated meaning, colorful writing, clarity, or evocative comparison. It uses an ordinary sentence to refer to something without directly stating it.
A simile is a type of figurative language used to make comparisons between two different things. The purpose is to say those things have some characteristic in common. Similes need support words to make the comparison, such as "like" and "as". An example of simile would be: She has eyes as deep lakes. - Because her eyes are blue they are being compared to lakes.
Similes can also use "as... as", which is precisely what we have in "as dead as a doornail" in the passage. This expression is used to emphasize death. If you say someone was as dead as a doornail, you mean they were certainly dead, "very dead", so to speak.
