Attachment and insecurity issues can be greatly improved with psychedelic induced trips (with safe setting). If mushrooms, ayahuasca or similars are very hard to get(in my country it's hard) holotropic breathwork is reported to have similar effect, although can't reinforce that.

This message is more like to anyone with attachment issues, I've just read your brother is 13 years old so mehh, don't know.. Safe bet that he is not mature enough, haven't read anything about what are the hazards when adolescents take it.