It's a very grave sin. The only way a homosexual can be saved is to turn away from it and stop practicing homosexuality. Repent and ask for God's forgiveness and never do it again. A homosexual who carries on and does not turn away from it and does not repent will be automatically sentenced to eternal punishment on that. God has the permanent cure for this problem.
Revelation 21:8 ESV
But as for the cowardly, the faithless, the detestable, as for murderers, the sexually immoral, sorcerers, idolaters, and all liars, their portion will be in the lake that burns with fire and sulfur, which is the second death.”
Jude 1:7 ESV
Just as Sodom and Gomorrah and the surrounding cities, which likewise indulged in sexual immorality and pursued unnatural desire, serve as an example by undergoing a punishment of eternal fire.
Leviticus 20:13 ESV
If a man lies with a male as with a woman, both of them have committed an abomination; they shall surely be put to death; their blood is upon them.
Exodus 22:19 ESV
“Whoever lies with an animal shall be put to death. (ok i know this one is not exactly about homosexuals but since homosexuals are animals i thought i'd add it anyway)