Mormons do NOT believe Jesus and the Devil are brothers. "My mother and my brethren are these which hear the word of God, and do it" (Luke 8.21; Matthew 12.50; Mark 3.35). The Devil does not do the will of God but opposes it, therefore he is not Jesus' brother. But Huckabee and the Devil are brothers because they lie about their brothers. I could equally say, "Baptists believe that Jesus and Hitler are brothers!" Wow, it's true, since Jesus became a human, all mankind are his brothers pertaining to the flesh. But such a statement is equally misleading about Evangelicals as the Huckabee's statement is about Mormons.
Interestingly, Lactantius, a famous Christian teacher who lived at the end of the third century, claimed that Jesus is the Devil's older brother. Lactantius believed that Jesus is God's eldest or firstbegotten Son, and the angels are God's younger sons. Since the Devil was originally an Angel, he USED TO BE a brother of Jesus. At least that's what Lactantius believed. See Lactantius, Divine Institutes II, 9, in Giovanni Papini, The Devil (New York: Dutton, 1954), 81-82.
Lactantius has a point since the Bible says, "Where wast thou when I laid the foundations of the earth? When the morning stars sang together, and all the sons of God shouted for joy?" (Job 38.4,7), and, "there was a day when the sons of God came to present themselve before the LORD, and Satan came also among them" (Job 1.6,12; 2.1,7). All the angels are sons of God (Psalms 82.1,6), and Jesus is the Son of God, so obviously the angels and Jesus are brothers. But here's the rub Huckabee! Didn't you know that Satan originally lived in heaven and was one of the angels (Luke 10.18; Isaiah 14.12-15; Ezekiel 28.13-19; Rev 12.4,7-9) but is now a fallen angel (Jude 1.6,9; 2 Peter 2.4; Rev 12.4,7-9)? I guess it doesn't sound so un-Christian to say Jesus and the sons of God are 'brothers' does it?
The holy Bible teaches that Jesus is God's firstborn Son, "he bringeth his firstbegotten into the world" (Hebrews 1.6). So if "God is spirit" (Jo 4.24), and our Lord Jesus "is spirit" (2 Corinthians 3.18), and God "maketh his angels spirits" (Hebrews 1.7), and God our Father is "the Father of spirits" (Hebrews 12.9) of all men's spirits, then clearly God, Jesus, human spirits, and angelic spirits all share one spiritual nature since we are all spirits. "I bow my knees unto the Father of our Lord Jesus Chirst, of whom the whole family in heaven and earth is named" (Ephesians 3.14-15). "One God and Father of all" (Eph 4.6), "the God and Father of our Lord Jesus Christ" (Ephesians 1.3,17; 2 Corinthians 11.31). "But be not ye called Rabbi: for one is your Master, even Christ; and all ye are brethren. And call no man your father upon the earth; for one is your Father, which is in heaven" (Matthew 23.8-9). "Have we not all one Father? hath not one God created us? why do we deal treacherously every man against his brother?" (Malachi 2.10).
"Worship the Father in spirit and in truth. God is a spirit, and they that worship him must worship him in spirit and in truth. Worship the Father" (Jo 4.23-24). Jesus has one and the same Father that we all have, "go tell my brethren, I ascend to my Father and your Father, to my God and your God" (Jo 20.17), and, "For it was fitting for him, for whom are all thigns, and by whom are all thigns, in bringing many sons unto glory, to make the captain of their salvation [Jesus] perfect through sufferings. For both he that sanctifieth [Jesus] and they who are sanctified [many sons] are all of one [Father]: for which cause he is not ashamed to call them brethren. Forasmuch then as the children are partakers of the flesh and blood, he also himself likewise took part of the same. Wherefore in all things it behoved him to be made like unto his brethren" (Hebrews 2.11,14,17; Ps 22.22; etc.). The angels don't want to be worshipped "for I am thy fellowservant, and of thy brethren the prophets" (Rev 22.9; 19.10). So Jesus is the brother of the sons of God, and the sons of God are brothers of the angels who are also sons of God. Minister Huckabee does not believe God's Word but follows man's word.