My dear friend left our faith

For context, we live in a country where most people are Christian. I embraced Islam three years ago, and he converted a year and a half back. We've been close friends for about six years. A few months ago, he started hanging out with the wrong crowd and got into a relationship with a girl. Around that time, he also began smoking weed and drinking alcohol, but he kept it hidden from me. When he finally told me about the girl, I advised him many times to keep his distance from her because she could harm his iman. Once I found out about the other things he was doing, I confronted him and said, "Look, brother, I care about you deeply, but I can't support what you're doing. So for now, let's put our friendship on hold." About two months later, I messaged him, "Assalamu alaikum, let's meet up." He replied, "I no longer follow Islam," and didn't want to explain why. I know that we cannot guide whom we love, but Allah guides whom He wills. Still, I've been feeling really down about it, and I feel powerless to change anything.