The short answer is: Kevin.

Renee figured out Andrew’s attraction first, Kevin picked up on Neil’s attraction not much later, and Kevin was the first to realize that it was mutual attraction with feels involved.

Renee had the advantage of knowing for sure that Andrew was gay, so once Andrew stopped seeing Neil as a mole and absorbed him into his makeshift family, she wondered if there was more going on. She asked him about it once, but Andrew of course brushed it off. Renee knew better than to push matters and decided to just keep an eye on things.

((I keep thinking I posted that snippet of theirs, the til death do us part accusation, but I can’t remember right now which Ask it would’ve been associated with.))

Neil, on the other hand, was a much harder read for her, because Neil avoided being alone with her unless he really needed something or had no choice. Most of what Renee saw of Neil & knew about Neil was Neil as he related to Kevin. She hoped, for Andrew’s sake, that it was an actual Thing with them, but she couldn’t pin it down with any certainty.

((When spring came and the upperclassmen started kicking around the idea that there might be something there, Renee was prohibited from betting on Andrew & Neil as an item. She could bet on Neil’s sexuality, but not his chances with Andrew, in part because her association with Andrew meant she might have insider details and in part because her betting would have influenced the substantial Andrew & Renee pool.))

Kevin, on the other hand, was too obsessed with Andrew and Neil to not notice how much time they spent looking for each other. Honestly, he was in the best position to assume they were going to work out their tension in the bedroom, considering he hailed from the Ravens. The Ravens were a violent hive mind and they were exceptionally isolationist. They weren’t allowed to associate with anyone who wasn’t on the team or part of school faculty, which meant the Ravens were possibly the most inbred team in the nation. Lot of sex going on in the Nest, fueled by anger & hate & tension & triumph. Almost didn’t matter who fucked who or what gender the other person was because in the end it was just sex and they were all Ravens. Most of the Ravens still identify as straight.

((Kevin & Thea were a secret not because they were sleeping together but because they wanted more than what everyone else had. They wanted something real, something ongoing and equal, and that kind of dedication would have been destroyed by the master before it could distract them from their purpose as athletes))

Everything from Neil’s reaction to Drake onward made it a little obvious that there might be more to it than could be cured by a rough tumble or two, but the gdi it’s a real thing moment happened when Neil went so completely out of character and sacrificed himself to Riko for Christmas.

If Kevin thought Neil had any chances of surviving the year, he might’ve sat both Andrew & Neil down in January and warned them about discretion and the lingering prejudices of the professional world, but he knew Neil was going to die in a couple months. For once in his life he decided not to put salt in an open wound.