@MrMazda:
I think the other thing that may be helpful to point out if he studies the scripture is to remind him about Matthew 7:1-3โฆ. More particularly, where it begins "Judge not, lest ye be judged"... It may also be helpful to remind him that while the whole concept of being gay may be seen as being wrong for one reason or another, if you're both happy with each other, why does it need to be any different than any other relationship?
"JUDGE NOT, LEST YE BE JUDGED" is an often misquoted scripture.
Let's look at the passage in its context:
MATTHEW 7:1-5:
"Judge not, that ye be not judged. For with what judgment ye judge, ye shall be judged: and with what measure ye mete, it shall be measured to you again. And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye? Or how wilt thou say to thy brother, Let me pull the mote out of thine eye; and behold, a beam is in thine own eye? Thou hypocrite, first cast out the beam out of thine own eye; and then shalt thou see clearly to cast the mote out of thy brother's eye."
Clearly, it is hypocritical judgment that this Scripture condemns. A hypocritical judgment is judging something for something of which you are also guilty - LIKE TELLING ME NOT TO JUDGE WHEN YOU ARE JUDGING ME! This passage means the opposite of what hypocrites often interpret it to mean! Jesus' point is for hypocrites to pluck the beam of sin out of their own eye so that they can see clearly to cast the mote out of their neighbor's eye.