What should I do if a family member has extreme beliefs and threatens me over them?

I was born into a Muslim family, and one of my family members has very extreme beliefs (like supporting ISIS). I’ve lived with this my whole life because I didn’t choose this situation.

Whenever we talk about religion, he calls me a “kafir” and says things like it would be better if I died. He has even told me that if there were no laws stopping him, I would have been dead a long time ago. We argue a lot because I don’t agree with his views at all.

The problem is I feel stuck. I can’t report him to the authorities because it would cause huge problems in my family, and I don’t want to be the reason my parents lose their favorite son and in the same time he is my brother !! ( he is 10 years older than me ) he talks about religion the whole time and the system isn’t good and he just want ISIS to take over the world and talking about violence the whole time i can’t take it too much OF VIOLONCE I hated this religion because of him and this islamic thoughts ! But at the same time, my parents don’t seem to see anything wrong with his mindset, even though it’s extreme and scary ( we are arabs btw - but i don’t agree with them at all )

Right now, all I do is argue with him, and it’s exhausting and stressful. I don’t feel safe or understood they do support him ans their islam

How can i deal with this situation pls ?