Guy gets asked to infiltrate a compound where brainwashing and cult tactics (plus drugs/chemicals) are being used to turn men into women. He happens to be trans, but also a expert on cult indoctrination and brainwashing techniques. Keeps track of time using coat hangers at one point.

Group name similar to the "Church of Achelois". Rank progression including Near Sisters and full Sisters. They'd been taken criminals and homeless men off the streets who nobody would miss.

He gets singled out for embracing his femininity, before being involved in an outing. During this outing, he manages to get leverage enough on the group to convince them that they should become legit as a charitable organisation instead of being a criminal ring. Story ends with him reaching out to another homeless man, and offering a purpose in life.

If anyone finds it, it would be greatly appreciated. If I ran into it elsewhere and it isn't here, such is the way of things - but I want to try here first!