I'm fluent in both languages so I'll translate for both parts
Basically what he says is this:
"He was training his sneasel, he lvl up to 99 then he equipped razor claw and give it the last candy to get to lvl 100.. The pokemon didn't evolve (the sign to evolve didn't show up), so now he has a useless lvl 100 Sneasel."
My personal answer is that: for sure you did this during daytime and if you read bulbapedia, celebi or in any pokemon game, you have to do this AT NIGHT to be able to evolve him. Quoted from bulbapedia: "It evolves into Weavile when leveled up holding a Razor Claw during the night."
Mi respuesta, ahora en espaniol para que la entiendas es la siguiente: seguramente le diste el ultimo caramelo de dia, y en cualquier juego de pokemon, en cualquier lugar que te fijes te aclara que tenes que tener equipada la razor claw Y tiene que ser DE NOCHE si o si.... Si el caso es que vos lo hiciste de dia, entonces no es un bug, sino mas bien es culpa tuya por no informarte antes, asi que...mala suerte... a buscar y entrenar otro.