Kylo Ren descobriu isso?

Muitos spoilers

The movie evokes Return of the Jedi (when Luke and Vader have a moment through The Force while on passing ships) in the moments before the attack. Kylo Ren can sense his mother on the ship (the camera switched back and forth between the two just as it did in ROTJ). He didn't hesitate with his father, but he can feel his mother through The Force... and then another fighter does the deed for him.

Even with that distance between them after the attack, it's a pretty safe bet he could feel her when she uses The Force to reach out and pull herself back on board. In the off chance Ren didn't notice, there's almost no chance Snoke didn't, and he would have used it to make another dig at Kylo Ren (and gin up that anger Sith thrive on, just as he did in saying he was mistaken about Ren being another Vader).

Kylo Ren sabe que sua mãe sobreviveu.

He picked up two small objects from the ground. A pair of chance cubes, strung together. Ren knew the dice well. They had been Han’s, hanging in the cockpit of The Millennium Falcon.

Ren glimpsed the ship through the Force. Rey and Leia were boarding. Both seemed upset by something.

_{^{The Last Jedi: Junior Novelisation}}

Nunca mais o vemos aprendendo sobre essa informação na tela.

Dito isso, vimos que as pessoas que são strongs na Força tendem a saber quando alguém próximo a elas morre.

Kylo Ren obviamente ainda tem uma conexão com Leia, mas não temos como saber se essa conexão foi mantida após

Leia was ejected into space.

É certamente possível que Kylo saiba

She had survived that

mas não está claro para mim se ele estava ciente de que ela

Made it to the salt-covered planet with the transports.

Leia certamente não parece pensar que ele saberá, já que ela

remains confident that the First Order will not realize the Rebels evacuated to the secret base

mas, em sua conversa posterior, diz

that she knows Kylo is beyond salvation, and is entirely committed to the First Order.

Assim, devemos supor que ela tinha razão para pensar que ele esperava que ela estivesse morta ou que não fosse capaz de localizá-la através da Força. Talvez ela tenha tomado medidas para esconder sua presença?

Isso não quer dizer, no entanto, que a Kylo não tenha conhecimento de

Leia's survival

após os eventos do filme. Dado que a liderança Rebelde tende a ser conhecida pela liderança do Império / Primeira Ordem, é justo assumir que a Rebelião renovada não faria segredo de seu status.