If He is not alive then we will die in our sins and there will be no resurrection of the dead.
He is not a part of a trinity, He is part of a Duality - the Father and The Son - God with God. The Son sits in heaven at The Father's right hand. The Holy Spirit is their Power.
2 John 1:9 (KJV) Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son.
He that does not abide in the teaching of Christ has not got God. He that abides in the teaching of Christ has both the Father and The Son. This means the teaching that the Godhead is a Duality is the correct teaching and the trinity is a heinous blasphemy.
John then goes on to say:
2 John 1:10-11 (KJV) If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed: 11 For he that biddeth him God speed is partaker of his evil deeds.
Looking pretty grim for all you mainstream trinitarians. Still not to worry, there is always time for repentance.