The figurative language device used is the simile. This can be seen when Trevor claims that the relationship between him and Teddy was like a "house on fire."
We can arrive at this answer because:
The simile is a figure of speech that allows an explicit comparison to be made between two elements.
This type of comparison is always performed using the words "like" or "as."
When Trevor talks about his relationship with Teddy, he states that "Teddy and I got along like a house on fire," allowing the simile to be noticed.
