this poke has a damage of 2.6k with flametrower and 2.8k fire blast and his destine bond hits 6.8k are not movements of their nature to remove so much, I hope you keep in mind.
Weezing does not have those fire spells in its moveset, tha's first thing.
That it is of poison type, that does not mean, that it can learn only poison moves. It can learn much more. https://bulbapedia.bulbagarden.net/wiki/Weezing_(Pokémon)