Let me answer his question.
Yes. Just as much as you, sir, are the brother of Adolf Hitler.
Latter-day Saints believe that Jesus, angels, and mankind are spirit brothers and sisters of God. Some of God's children, Satan being the principle one, rebelled against God and fell from Heaven. They are, in fact, our brothers and sisters in the most strict sense, but we are definitely estranged from each other.
This should come as no surprise to any student of Christian History, however. The early pre-nicene Church father Lactantius wrote:
- Since God was possessed of the greatest foresight for planning, and of the greatest skill for carrying out in action, before He commenced this business of the world,--inasmuch as there was in Him, and always is, the fountain of full and most complete goodness,--in order that goodness might spring as a stream from Him, and might flow forth afar, He produced a Spirit like to Himself, who might be endowed with the perfections of God the Father... Then He made another being, in whom the disposition of the divine origin did not remain. Therefore he was infected with his own envy as with poison, and passed from good to evil; and at his own will, which had been given to him by God unfettered, he acquired for himself a contrary name. From which it appears that the source of all evils is envy. For he envied his predecessor, who through his steadfastness is acceptable and dear to God the Father. This being, who from good became evil by his own act, is called by the Greeks diabolus: we call him accuser, because he reports to God the faults to which he himself entices us. God, therefore, when He began the fabric of the world, set over the whole work that first and greatest Son, and used Him at the same time as a counselor and artificer, in planning, arranging, and accomplishing, since He is complete both in knowledge, and judgment, and power... (Lactantius, Divine Institutes 2.9. in Alexander Roberts and James Donaldson, eds. The Ante-Nicene Fathers, 10 vols. (1885; reprint, Peabody: Hendrickson, 2004), 7:52–53.)
Many things he here taught are not considered "orthodox" by today's standards. However, Lactantius was definitely orthodox during his lifetime. Amazingly, many things here correspond to LDS doctrine precisely in those areas that are "unorthodox." For example,
1. "He produced a Spirit like to Himself," namely Christ. Christ, in this sense, is not the "co-equal," "eternally begotten," "same substance" "persona" of the later creeds, but is a spirit Son of God.
2. "Then [God] made another being, in whom the disposition of the divine origin did not remain." God made another spirit who rebelled and who fell from his exalted status. He became "the diabolus," meaning "the devil."
3. Christ is the "first and greatest Son." He is not the only son, but the first and greatest.
4. Lastly, since the diabolus and Christ are both spirit sons of God, they are spirit brothers.
Christ is unique in several respects from all other spirit children of God:
- Jesus was and is perfect
- Jesus is God (See John 1:1-2, Hebrews 1:6, 1 Nephi 11:16–26, D&C 76:13).
- Jesus is the Creator (See John 1:3, Hebrews 1:1–6, Mosiah 3:3, Helaman 14:12, Moses 2:1).
- Jesus obeyed the Father in all things (See 3 Nephi 11:11).
- Jesus was chosen and foreordained to be the Redeemer (See Isaiah 43:11, Mosiah 13:28–34, 3 Nephi 9:15, Moses 4:2).
- Jesus is the Mediator between God and humanity (See John 14:6, 1 Timothy 2:5, Hebrews 8:5, 2 Nephi 2:28, D&C 76:69).
- Jesus was "the Only Begotten"—only He, of all God's children, had a physical inheritance in His body from God the Father. All other mortals have two mortal parents, and Satan and his followers never receive physical bodies at all. (See John 1:14, John 3:16, John 14:3, Jacob 4:11, Alma 12:33–34).