Five questions to address, let's begin.
1:What is blasphemy against the Holy Spirit according to Evangel?
To blaspheme the Holy Spirit is when you are so evil, you attack the Spirit of God and attribute the works of the devil. See the following verses: Mark 3:28-30, Matthew 12:31-32, Luke 12:10.
2:Can a believer or non-believer blaspheme the Holy Spirit today?
A believer in Jesus cannot do this, If they could, they would have no remorse or fear. Blasphemy of the Holy Spirit can happen today, although it is not common and only an unbeliever is capable of this or an apostate from the faith.
3:Is blasphemy against the Holy spirit an eternal sin without forgiveness?
It's eternal, because the one who commits it, cuts themselves off from the very entity that Jesus sends to the believer to regenerate them.
4:Who will forgive blasphemy against the Holy Spirit?
No one, because it is an unforgivable sin.
5:If guilty of eternal sin, what hope can be offered those eternally damned without forgiveness?
If the person believes that they have committed blasphemy of the Holy Spirit, it's a 100% chance that it hasn't happened. Those who have attacked the Holy Spirit and have no fear, are the ones who have no hope of salvation.