Yes, we believe that Jesus and Satan were brothers. If Lucifer fell from heaven, then what was Lucifer before he fell? We believe that Jesus is the firstborn of all the spirit children of God. We believe that all mankind existed before the foundation of this world and we were all children of God the Father and brothers and sisters of Jesus Christ. He is our Elder Brother in the spirit. Lucifer was also a son of God the Father and a brother of Jesus Christ. But he rebelled against the Father and started the war in heaven (see Rev. 12). 1/3 of all the hosts of heaven sided with Lucifer and became his angels. Thus Lucifer was cast out of heaven along with his followers, and he was renamed Perdition, Satan, and the Devil. He and his followers were all the offspring of our Father in Heaven but have lost their salvation for coming out in open rebellion against God. They were cast out of heaven into the earth and the war that was in heaven goes on even today here on earth. Satan is trying to make us also fall from the grace of God and be damned just as he and his follower are damned.Not according to the Mormons I know. They say that they Bible has been mistranslated and they teach that Jesus and Satan are brothers.
There are some verses that over the few thousand years of compilation and translation were mistranslated but overall we believe that the majority of the Bible is the word of God and we consider it part of our canon of scripture.