Tantra
The novel features a character who is silently experiencing a deeply tantric experience of self. Another way to say this might be to analyze the emotionally intimate relationship between Bong Bong and Fresquito; they are the same in their gender, so the intimacy could be homosexual, or it could be that Fresquito is another person who experiences their self in such a tantric way that Bong Bong finds an analogy for self-love. He seems attracted to women, but when he has a beautiful woman who wants him, he cannot figure out how to become intimate with someone other than himself, and he hesitates and ultimately offends her by not eagerly participating with her sexually. In reality his experience of self is a source of intimacy with himself, and that is difficult to translate.
Queer identities
The word queer was gradually applied to sexual and gender identities through natural usage because the word meant "strange" or "perplexing." A person's experience of sexuality can make their personality perplexing, and this novel is a subtle demonstration of that nuance. The story is not openly homosexual, so Bong Bong could be assumed to be a closet homosexual or repressed, but that is just wanton assumption with no evidence. Better is to consider that Bong Bong is having an experience of his own sexuality which does not fit into the prescribed boxes that our labels suggests. His girlfriend calls him crazy and insane, but the reader has the opportunity to say that he is simply out-of-the-ordinary.
Paranoia
Now, the issue of insanity is one of moral and psychological implications. There is a sense in which Charmaine's accusations are intended with shame, as if to suggest that in Bong Bong's private practice of self-relationship and self-government, he might have indulged in modes of psychological experience which could be shameful if brought to light (that is what we learn from Bong Bong's sister who feels embarrassed and confused by Bong Bong). By the end of his journey, he has been proven so unique that his community is baffled by his femininity, his reservation, and his powerful imagination for paranoia.
America as imagery
Bong Bong's heroic journey into the chaos of his own self starts with the inciting incident of his removal from home and his voyage to America where his parents think he is in school. In reality, he is accepting the imagery of American life as his education. He examines the human experience by contrasting Americans and their way of life to those in his community back home. For him, the imagery seems enticing. We know this because the sister comments that she is seeing a side of Bong Bong which is confusing to her, and she wonders if the context of American ideals is making him curious about his sexuality.