Extremely rude foster

We’ve had a 15 year old boy in our care for a few months now. Our first teen. He is just rude and sarcastic and negative all the time and it’s really starting to get to me.

First thing he does when he gets there is ask where his room is and what our rules are. I show him his room but I tell him there’s no rush to worry about rules I was just hoping we could get to know each other a bit first.

He says “I don’t care about you and you don’t care about me so let’s just stop with this charade okay?”

He spends all his time in his room and hardly speaks to us. Constantly tells us to stay out of his life when we ask the most basic questions or give the most basic guidance.

His birthday is coming up and I asked him what he might want to do and he said “who told you that? That’s none of your business.”

Yesterday he told me “just stop pretending you care about me it’s so annoying” and stormed off to his room. He keeps saying he won’t be here long so there’s no point in getting to know each other.

My husband says he’s probably been through a lot so just allow him to be angry. I get that. I just feel like his mood is really pulling everyone in the house down and it’s making being in my own home really uncomfortable and like I’m walking on eggshells in my own home waiting for him to blow up on me again. My husband says at least he hasn’t done anything illegal or dangerous yet. I just feel this is really unhealthy for all of us.

I don’t mean to sound like I’m complaining or it’s all about me. I want to help and support him but it seems everything I do is the wrong thing. But I feel bad just ignoring him but that seems like what he wants. Any tips? I almost want to say it’s okay to hate us and we can ignore each other if you want but some basic politeness shouldn’t be too hard since we are all under the same roof.