This is an obvious derivative of "Mysterious Skin" (2004) by Gregg Araki. That film is about a young man who believes he was abducted by aliens as a child. He places another boy his age in this memory who has grown up into a gay teenager living dangerously on the edge. When they eventually meet, the reason for the abduction is revealed to be the same as in this film.
It is possible for two people to come up with the same idea within 20 years. But it is not possible that no one notices the similarities. So a credit to Araki or Scott Heim, who wrote the novel, would have been in order. There is none, so this is a case of plagiarism.
The film by itself is OK if you can tolerate rotoscope animation. But its artistry compares poorly to that of "Mysterious Skin", perhaps the greatest films about this subject ever made.