I was not bought up in a Christian household and my immediate (and beyond) are all unbelivers to my knowledge. There is two issues I'm struggling with, - the first is being treated as an outsider by my parents and siblings due to my strong beliefs (I have only been a God fearing Christian for 3 years or so). But it's like I cannot talk to them the same way I used to because I'm not the same person. My mother actually threw away one of Bibles. The second is dealing with the hurt of knowing they are unsaved. I struggle with it every day and pray for their hearts to be unhardenend. It's like knowing your loved ones will die in a plane crash and not being able to stop them getting on it.
I'm not the best person to give a reply, as my father died several years before I became a Christian, and I'm almost certain he's in Hell, due to a peculiar event that happened the night he died (when I was still an atheist) viz. he appeared in my room, we talked and argued, and at the very end he gave this absolutely terrifying scream and then just disappeared. I don't miss him - he was far too cruel for that for the first 20 years of my life - but I'm pretty sure he's lost.
My mother and sister died some years after I became Christian. I'm not sure where my mother is (Purgatory I hope, since I'm Catholic), and I suspect my sister might get to heaven eventually. They're all dead, and I'm the only one left. I did pray fairly consistently for them at one stage, but I got a bit disillusioned since God didn't seem to be doing His bit.
But God won't interfere with our free will. He may knock quite loudly sometimes, but we still have to open the door. We're fond of talking about the Father's loving response to the prodigal son, but we overlook the fact the prodigal son had to come to his senses
first.
Sometimes you've just got to let God be the one in charge. He's the judge, not us.
People have free will, including the members of your family. They can choose for God or against Him. As Christ put it, he who loves father of mother more than Him is not worthy of Him, and on His account mother will be against daughter in law etc. etc. We call Him the prince of peace, but one of His forthright declarations was that He did not come to bring peace to the earth - instead He brought division, and you're seeing that within your own family.
They're hard words, but that's the way it is.
In the meantime you might have to keep some distance, and grow more in your own faith first and stick close to your church. You may need to find a "family group" in your church - people you can rely on and get along with, and whose company you enjoy.
In the final analysis the best witness is
personal example. If they see you gradually changing for the better, then you might see some positive response. But don't expect overnight conversions - they're quite rare.