In laws when not married? Newbie here

So I’m new to this stuff and finally am in my first relationship. My 25m bf talks about his 29f sister and 27m brother and his 25f wife quite a bit and I am excited to meet them. He says his sister adores me so far and enjoyed my photography heavy Instagram. She agreed to have us stay with her in Philly so we will do a short road trip soon. He also suggests I would get along well with his sister in law who immigrated from Afghanistan and had many cats back home. I understand they aren’t actually my in laws but it is important to me that I show them I value their opinions and cultivating our relationship besides what I have with my boyfriend. My bf knows I am a eager to please as is my nature, and I want to meet his siblings to lessen the pain of my big sister’s passing ~1.5y ago.

I am in a good place where I could ask my bf what to refer to them as but I also wanted opinions. In an interfaith and interracial relationship, I am nervous about his parents approval. I wonder, for most girlfriends, how did you begin and maintain a friendly relationship with your mans family? Traditionally Muslims are supposed to hate Jews and vice versa so I expect skepticism of our pairing. I was clear to him I was learning Arabic well before we met and would be fine with Muslim kids with elements of my culture as well. My extended family is not going to be happy but they all live on the west coast so I’m not terribly worried.

Thank you😌💕