I might end up shipping him with FMC if he's not as bad as he's letting on, because I get the sense he tries to build a wall around himself of acting immoral to avoid getting close to people.
Given that there are already 7 volume covers available (not a spoiler BTW) and that this is only volume 3,
it's reasonable to assume this SD card won't contain the smoking gun evidence needed to end this mystery.
They are using the brothers, just happens the older one figured it out, everybody is various degrees of shit in this manga, minus the younger brother so far.