Brunetto Latini appears in Inferno 15 among the sodomites in the seventh circle of Hell. Readers often notice the tenderness Dante exhibits toward his mentor and the affection Brunetto expresses for Dante. Brunetto uses “son” as a term of endearment during their encounter (Inf 15.31, 37), and Dante describes walking beside Brunetto “with head bent low /as does a man who goes in reverence” (Inf 15.44-45). While Dante uses the formal second person pronoun, voi, to address Brunetto, he speaks to Dante using the informal tu, signifying Dante’s deference to his mentor. At the end of the canto Brunetto pleads, “Let my Tesoro, in which I still live, /be precious to you; and I ask no more” (Inf 15.118-120) 😉 This could be a reference to Latini’s encyclopedic work in French, Li Livres dou Trésor, but could also refer to his poem, the Tesoretto 😉 
In Dante’s text, in Inferno XIII, we meet a major counter figure to Brunetto Latini. It is a scene of terror, where Dante plucks a dead twig which then bleeds __ one can add that it bleeds brown chancery ink __ and speaks. Later Dante gathers up the fallen leaves, the folia, restoring them to their owner.1 The shade who is the speaking tree is the suicide Pier delle Vigne, Chancellor to the Emperor Frederick II of Sicily. Pier delle Vigne as imperial logothete functioned much as had Thomas à Becket for his king and as would Thomas More to his; he had run the imperial chancery and likewise taught students how to do so.2 Part of his teaching method
was to have exempla of his letters be copied into a collection, the Epistolarium.3 We find that letter collection in Florence translated into Italian and continued by Ser Brunetto Latini, to be copied out by his students, including the letter traditionally considered to have been composed by Brunetto Latini himself and sent to Pavia after the Florentine murder of the Abbot Tesauro of Vallombrosa. It is clearly ascribed to him in a Vatican manuscript.4 
Blair Moore from digitaldante.columbia.edu
provide additional insight. I having written on Dante’s progressive treatment of sodomy — progressive, of course, with respect to his cultural context — in the essays “Dante’s Sympathy for the Other” and “Contemporaries Who Found Heterodoxy in Dante” (both are cited in Coordinated Reading). In “Dante’s Sympathy for the Other”, providing ample visual documentation, I place Dante’s treatment of sodomy in the context of contemporary eschatological artwork, for instance Giotto’s Last Judgment in the Scrovegni Chapel in Padova and Taddeo di Bartolo’s Last Judgment in the Collegiata di San Gimignano (ca. 1396). Giotto’s treatment of the lustful features graphic images of what art historians Anna Derbes and Mark Sandona call “torments directed at genitalia” (The Usurer’s Heart, p. 66). Taddeo di Bartolo depicts a sodomite “skewered from mouth to rear by a pole” (The Usurer’s Heart, p. 66). (edited by Diana Ramos from Hanzhong, China on April 19, 2021) 
Pulling at the pilgrim’s hem is a scorched, unrecognizable sinner. After a few moments, Dante realizes the man is his old teacher Brunetto Latini, who is now among the sodomites. Siete voi qui, ser Brunetto? Dante asks. Are you here, ser Brunetto? This warm, perhaps even affectionate question is underscored, Hollander explains, by something else: “I think he is also asking ‘Are you, wonderful man, down here among the scum?’” It seems, at first, a tender scene: Dante asks if Brunetto will sit with him, and for the first time we see Dante speaking to a sinner about himself and his journey, not standing idly by as a sinner tells his story. It even seems as if the two are catching up. For this reason, Hollander says, readers and critics are often charmed by this scene, but they never examine the relationship between Dante and Brunetto as carefully as they should. Dante’s treatment of Brunetto is colder than it appears.