After Finn's little warm story about how he became what he is today, there was just outright silence in the car as Dirsan just tried to make sense of all of it. He didn't speak, didn't glance at the mirror… he just tried to process all of it… that simply Finn had murdered his whole family.
Like it was clear to everyone that the Bellini family has many people from many backgrounds with traumas and things that are just dark… but this one was the top of all of it… the darkest of all the stories he heard so far… and he knew he would never forget it and the second he could never look at Finn with the same eyes as he did before.
Though Finn himself didn't really seem to care about it, he was just relaxing with his eyes closed as they were making their way to another meeting where he could finally buy the white magic and the greenweed.