When a person believes that he/she is saved because he/she has accepted Jesus ” man” as his Savior and Lord but denies that Jesus Christ is the Son of God and Christ Himself is God, is he/she saved? In other words, could a man be saved from his sins by putting his trust in Jesus “man” but denies that Jesus Christ is God/Man, is he saved?
God’s law requires that the blood of an innocent (sinless) man is necessary to redeem us from the penalty due us for our sins. But there has never been a sinless man because every man since Adam has inherited a sin nature that makes it impossible for us to avoid sinning. This is why God Himself had to become a man and die in our place. Otherwise any good man could have given his life in exchange for ours.
But the person you’re referring to has another problem because the Bible clearly states that Jesus is God in the flesh. John said so in his Gospel (John 1:1), Paul said so in Colossians 1:15-20. The writer to the Hebrews said so in Hebrews 1:3, Jesus said so in John 10:30 and John 14:9, and God Himself said so in Hebrews 1:8. In Revelation 1:8, God said, “I am the Alpha and the Omega” and in Rev. 22:13, Jesus said, “I am the Alpha and the Omega.” The only way this could be true of both is if they are one and the same.
To deny the deity of Jesus is to deny the claims of God’s word concerning Him. If a person does so in ignorance, he might be forgiven. But if he has studied the Bible and rejected it, then I think you could reasonably question his salvation.