What is the ruling on shunning a friend due to his perversion and love for sodomy? Is it permissible to return evil with evil? And is what Ibn Taymiyyah said concerning this correct?

It is obligatory to advise someone who is deviant and has homosexual inclinations, and to explain the gravity of their act, and that it is one of the most abhorrent evils. If they do not heed the advice, then it is obligatory to avoid and shun them. A Muslim must choose the best companions and distance themselves from the wicked, in caution against the dire consequences of bad companionship, in accordance with the Almighty's saying: "And the Day the wrongdoer will bite on his hands [in regret] he will say, 'Oh, I wish I had taken with the Messenger a way. Oh, woe to me! Would that I had not taken such a one as a friend.'" And His saying: "Close friends, that Day, will be enemies to each other, except for the righteous." The Prophet, peace and blessings be upon him, said: "Do not accompany anyone but a believer, and let no one eat your food except a pious person," and "A person is on the religion of his intimate friend, so let one of you look at whom he befriends." Therefore, it is essential to beware of bad company and distance oneself from it, because it is contagious.

As for forgiveness, it is only good when it leads to betterment and its benefit is preponderant, as the Almighty said: "So whoever pardons and makes reconciliation - his reward is due from Allah."