So your friend is Akha and had twins and kept them right?
what I have heard is that Akha thinks only animals can have more than one child and that one will be possessed by evil the other is good, but one can not see the difference, therefore both must be killed.
I do not know about the man, but the girl can not be in the village next year and can not go to another village, but must live in the jungle. she is not allowed to see or talk to anyone during that time, but the village can provide her with food (however, they can talk to the "trees" nearby) one can not talk about twins in the village at all, so the young people who have not experienced it will not know the tradition until they get twins in the village.
since it is the traditional way the Akhas think, I'm interested in what would happen these days if such twins came back and visited the village. what will the village think and do and what about the parents?
if your friend is Akha it is possible to get in touch with him so I can learn a little more about the Akha traditions?