Ask yourself this are you hurting anyone by being a good friend? I totally support you doing it. I'm Catholic but I'm also a strong supporter of the LGBT because God made us all in his vision.
Tell that to Sodom and Gomorrah and the surrounding cities. When being a good friend supports and condones sexually immorality, then one has to draw the line and stand with the word of God. In the book of Revelation in the letter to the Ephesians, Jesus commends them proclaiming their good qualities and then rebukes them for falling from their love for Him. Then He says, "but you have this in your favor, you hate the practices of the Nicolaitans,
which I also hate. This was a group, just like with Balaam who taught Balak to entice the Israelites to commit sexual immorality. Therefore, what the Lord hates we should not support or condone, but believers should hate what the Lord hates. Now, that does not mean to hate them, but to warn them about the consequences of living that life style. To be clear, they have the freedom to continue living that life style, but the consequences are the same. Those who are willfully living according to the sinful nature will not inherit the kingdom of God.
That said, do you think that for Jameen to agree to be the best man at his gay friends wedding, where two men will be entering into the detestable practice of sexual immorality men with men, which the Lord hates, that Jameen will not be hurting anyone by his decision? First of all, by being present there as best man, he will be supporting and condoning that event, something the Lord hates, as well as taking part in contaminating the institution of marriage which God made only to be between a male and female.
"Have no fellowship with the fruitless deeds of darkness, but rather expose them."
By agreeing to be best man, he would not be exposing that deed as belonging to darkness, but supporting and condoning it.
You are correct in that, God did make all of us in His likeness, but then came the fall. Now He urges all people to believe in His Son and repent of the sinful nature. What you are suggesting above is from a sinful-world point of view and not from a Godly one.
If you are a strong supporter of the LGBTQ, then being a Catholic will not save you, for you are siding with the enemy. I would advise you to seek God regarding this, repent and reevaluate your position regarding this, because this thinking is not from the Spirit of God, but from the evil one.
"In like manner, Sodom and Gomorrah and the cities around them, who indulged in sexual immorality and pursued strange flesh, are on display as an example of those who sustain the punishment of eternal fire. " Jude 6