My brother isn’t a Muslim like me and he makes jokes a lot. I’m close with him but it’s hard cause he makes these jokes about Islam sometimes and I might laugh on accident or just stay quiet, and I’m really worried that these took me out of Islam. He made a joke about how the Quran sounds, I didn’t say anything, but I just made some other joke back with him. Do I have to repeat my conversion as a Muslim because of these situations? Sorry if this isn’t a good question but I just feel worried..because I know it’s one of the things that could make you a kufr.
assalamu alaikum you can choose to remain silent on his jokes. Allah sure take tests in our deen. you have to be very patient. You don't need to repeat your conversion. You can make du'a to Allah that he guide you brother not to make derogatory comments on the Holy Quran. may all show your brother the right path.