Even my worst trips I couldn't consider "bad" trips. Sometimes a new reality wheighs heavy on my brain for a while if I do too much. Like, I'll have an epiphany about the way things are and I feel helpless at times. He's probably lost in his thoughts right now and may need some help to see the "good" in the world. I'm wary of professional help, but just because it's not for me doesn't mean he won't benefit from it. The best you can do is talk to him and make him feel like he matters. We all need help from others sometimes.

If he has other drug problems it may be that he doesn't think he'll be ok without them. That he'd rather be high all the time than to feel the monotany of day to day life. Or maybe I'm just projecting because that's how I get sometimes.