I am a new player in a group. Another player's character supposedly spent their childhood in a brothel before being sold to pirates; they served on the ship's crew before eventually deciding to retire and get married, only to have their wife killed. The player himself is rather edgy and threatens PvP from time to time; being edgy seems to be a trend for him, since the other two characters of his that I have seen are edgy as well.
I only joined the gaming group three weeks ago (they were playing three games and I got to join all three), so I don't feel comfortable complaining about it. He is the argumentative sort, saying how his character being unlikable is the fault of the entire party rebuffing him (he is rebuffed because he's unlikable, rather than the other way around) after every session, and going as far as to say that his character could start PvP.
I am both new to the group and not in the state of mind where I can deal with that kind of person (social isolation and exams taking their toll from my mental state), so I don't know how to prevent him bringing up his character's past as it is bothering me since it involves a child in a brothel.
What can I do in this case? Should I talk to the GM or other players? Should I just refuse to acknowledge him?
From what I can tell (keeping in mind rest of their backstory), I think they want to play this to be "edgy". I am bothered due to not finding this thing acceptable as part of a game, especially if it doesn't contribute anything except "Well, my character lived in a brothel, so he's great at sex stuff".