^^ If he just had a bad trip i don't know if he should eat a "shitload" for his next trip....
I think he should give it another shot if he is feeling up to it in time, but before that its good to know what triggered it in the first place. Any number of things involving set and setting can trigger a bad trip... Unconcious problems/repressed shit comming to the surface, getting sketched out by authority figures, being overwhelmed by it all, loud music, asshole people, too many lights, strange body sensations, thought loops, thinking your insane, the list goes on forever.... Once you identify the cause you can work around it, if its part of where you tripped that caused it, just look for a better setting next time... If its something involving mindset, that can be worked out but its better if we know what type of thing triggered it.
As far as a psych goes that would help you get back into it without much worry of a bad trip goes, i reccomend 2c-b, 2c-i is nice if your the type who is fond of the visual over the mental aspect of hallucinogens.... All my experiences with 2c-b tell me that i could probably give it to a pretty nervous person and they would be able to handle it.... I have tripped on up to about 20mg around unknowing family who would care if they knew i was tripping...