Well I guess give him unconditional support. There is no telling whether someone may struggle with surfacing feelings or just have a careless trip, so try to be understanding even if things don't make sense. It's not his job to make you understand though, so that can be tough. See if you can figure out what he needs. Sometimes people get anxious or sensitive about something and they don't always find the words to express it. Like feelings of guilt or paranoia over tiny unimportant things. In such cases always try to comfort him by acknowledging your support and care.
In a lot of ways I think it can be like babysitting a small child. Emotionally people can get quite child-like on a number of psychedelics, but don't patronize them either because their intellect often does not regress.
If something goes wrong, offer to ground the tripping person. This can be tricky but it comes down to confirming a connection with something they can find certainty and safety in. Emphasize what is actually happening and that they are alright, help them not to get pulled into a boundless sea of unhelpful thought patterns.
However don't dismiss the validity of what they are going through, because even though a lot of it may not be real to you or even meaningful to the tripper... the experience as a whole tends to be meaningful in its own way. There can be lessons or insights despite potential confusion. Help the tripper to be guided through all of it and not to get stuck and fixated too much.
thank you!
