This is pretty common for very high dose DMT and it can certainly be alarming from a 3rd party perspective to see people react this way. It sounds to me like he pushed the dose higher than necessary, it also sounds like he may have pyrolized the material, that would account for the retching, burnt DMT is nasty stuff.
Tell him to be sure and carefully weigh his dose next time, 40-50 mg should be moar than enough for most people in most situations. Also to use some finesse with the fire, the idea is to vaporize it, burning as little as possible
Thanks for sharing your report, not a lot of people share the outsider perspective on it here and it's good reminder that people on DMT can do rather disconcerting things. No need to worry though, as pointed about above, the molecule is quite physiologically safe.