Is Boris a friend or a bad influence?

Sadly, Boris is a bad influence. Unfortunately, his circumstances as home..... where he lives with an abusive, alcoholic father, mean that he hasn't grown up in a loving household and often has to fend for himself..... and defend himself. In the end, however, Boris proves himself to be Theo's friend when he sticks around to help him recover the painting.

I think Boris is both. Yes, he is a bad influence, but the thing is that for someone like Theo wrapped up in severe Trauma and Depression, it is hard to find friends his age he would feel a deep connection to. Kids who experience severe Trauma grow up very fast, Kids at the same age living with a supportive, caring family are mostly sheltered from hard realities, and i won't say they are inmature, but their experience level is very different. Theo probably wouldn't even know what to talk about with them and feel very alone. Boris has grown up in a very abusive situation. Therefore he is always in search for the next level of kick. Yes he influences Theo to drink and take drugs, but he also is there for him when he wants to kill himself on multiple occasions. Theo cannot really open up to anyone about the bombing including Pippa, because she doesn't really want to talk about it, apart from Boris. Boris listens to him and shows empathy to Theo, even though he is a source to most of Theos problems. I compare Boris to the Joker in a deck of cards, he is a trickster, he can do good, he can do evil. Just depends on your moral code and the game your playing.