>>45347299He's taught his Pokemon his beliefs, but whether or not they choose to internalize them and follow them is up to them and usually on a case by case bases.
His Lilligant follows them about as well has he does. She's never killed anyone before, and I don't think she will unless the situation requires it.
His Gardevoir has killed before. Once he got shot at enough that he would have bled out in about 30 seconds and she was out at the time, she used Psychic and popped two peoples heads off. She believes in Brent's philosophy, but she just couldn't keep her composure after seeing Brent like that (especially because she was his main Pokemon in that fight, to her it felt like it was her fault). She hasn't killed since though and has been trying to be better since.
His Luxray respect's Brent's philosophy thinks its incredibly admirable, sweet, romantic... but she's straight up eaten Pokemon before and has little issue with killing something. She consumed a Shroomish after it fainted because she felt like it, she almost murdered and ate a Female Zubat because it looked at Brent funny. She's... a work in progress as far as this goes. She really likes fighting and being the best is important to her, its a part of being born in world of competition for mates and strength being valued more.
His Lopunny follows his beliefs pretty well. He hasn't slipped up yet, and maybe won't. He likes Brent a lot, and has seen first hand that showing some mercy to foes has actually done some good. A lot of people have been converted to his side after being enemies, hell all of Brent's Pokemon were befriended and shown mercy before joining. So he's doing good.
Primarina is old and kills only when necessary or if something pisses him off enough to warrant it. He's yet to kill anything we've fought.
Lastly, Medicham. He's very peaceful. He only kills as a last resort just like Brent. He doesn't need to be taught mercy he mastered that a long time ago before meeting Brent.