So, you can say like, "Because I knew my gay son was going to go to hell if he found a boyfriend, I chopped his head off. And that was the most compassionate thing I could do."
“思いやりがあるからこそ ゲイの息子が地獄へ行かなくても済むように 首を切り落としてあげた” と言えるでしょう