Anything that is not in the way that God originated it is sin. If the person is claiming that they're still homosexual and they expect to go to heaven, then they're contradicting the Bible in their beliefs!
1 Cor 6:9-11
9Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind,
10Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God.
11And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God.
If they're still homosexual, regardless of action on the attraction...they're not what God has commanded them to be, and I find it hard to be those people have been "washed, sanctified, or justified" as the Bible says. The Holy Spirit of God doesn't contradict himself.