pretty sure they hinted at brainwashing ? after his brother died (he was killed by a gang member i believe), manny was lost and hurt. i forget how he stumbled upon the church but the reverend there basically manipulated him and used his pain to convince him that it was his “god given” duty to remove the bad guys from the earth. they haven’t made it clear if he has any disorder but i believe he may just be compartmentalizing as a trauma response.
his brain is essentially making him forget he’s doing these things to lessen the guilt and the reverend also makes it worse as well but i think to some degree he is aware of his actions hence the last chapter with the confession.

Why is Manny killing those drug dealers again? I dont remember the reason why he started. Was it even Said in the story? Also is he like schizophrenic? Or have ptsd ?