Well,
I have made the experience in the past that other Muslims use this to start an attempt to convert others, or start a debate based on their ideology. I sincerely hope this isn't one such occasion, and you are genuinely interested in the Christian viewpoint on this matter.
Saying this, I can only write about what I believe, in no portion do I speak official church teaching, since I have no authority to speak for my church. I can only tell you what I have come to believe through my studies and the teachings of scholars I've met or read.
Jesus is one of the three persons of the holy trinity. He came into our history as a man, born to the virgin Mary. Thus he is 100% human, and 100% God. We as humans can die, so he was able to die, his body was able to die. Just as we are body and spirit, so Jesus took on body through birth and always is spirit.
God gave us spirit when he made Adam our first father, by breathing life into us. No other creature has received this breath of life. When our bodies die, our souls do not perish with it.