One literary device Shakespeare uses to characterize Friar Laurence as a father figure for Romeo is having the friar address Romeo using a term of address. Terms of address can be any title, name, word, or phrase that can be used to address someone. Terms of address can actually say a great deal about both the person speaking and the person being spoken to because a writer can use the term of address being said and how it's being said to classify different thoughts and emotions. For example, terms of address can show friendship, respect, animosity, subordination, and superiority. We see Friar Laurence using a term of address to address Romeo in the very first speech he says to Romeo. More specifically, when Romeo comes to find the friar at dawn, Friar Laurence says:
What early tongue so sweet saluteth me?
Young son, it argues a distempered head
So soon to bid good morrow to thy bed. (II.iii.33-35)
The term of address "young son" shows us that Friar Laurence does indeed feel fatherly towards Romeo. He feels that Romeo is young and needs a great deal of care and guidance.
A second literary device we see Shakespeare using to portray Friar Laurence as a father figure is a rhetorical scheme called antithesis. Antithesis is when two contrary ideas are expressed in the same sentence. Dr. Wheeler gives us the example, "Evil men fear authority; good men cherish it" (Wheeler, "Schemes"). In this same first speech, Friar Laurence uses antithesis to show the differences in his and Romeo's ages, which also portrays Friar Laurence as an older, wiser, authority figure, or father figure. The antithesis can be seen in the sentence:
Care keeps his watch in every old man's eye,
And where care lodges sleep will never lie;
But where unbruised youth with unstuff'd brain
Doth couch his limbs, there golden sleep doth reign. (36-39)
In these lines, Friar Laurence is arguing that Romeo has no reasons to be awake at this hour. The friar further argues that the reason why he himself is awake is because he is older and his mind is troubled; a troubled mind prevents sleep. However, Romeo should not be awake because he is young and ignorant, as we see in the phrase "unstuff'd brain," and, therefore, should have no difficulty sleeping. Since these lines contrast Friar Laurence's age and cares with Romeo's age and cares, it is a perfect example of antithesis. In addition, the contrast in ages shows us how exactly Friar Laurence is like a father figure to Romeo.