With which Pokemon do you start the fight? I guess with mawile? You can start off with it since it resist every single move from from Minior (You can maybe pump it up with Items like X Attack and such) try to keep your Mawile alive for Golisopod. (Explained down there)
I would personally switch out Camperut for Sharpedo since it outspeeds his entire team and can hit hard. If it has Rough Skin and Ice Fang you should use it against his Tyrantrum if still alive afterwards keep it for his Chandelure. If you are pretty lucky maybe and one-shot them (very unlikely) use it against his Toucannon afterwards it should have finished his job sent next in your Meowstic (learn him Charge Beam instead of Future Sight maybe, but this is just personal preference). He will send out his Golisopod next for sure since Type advantage, switch out for your Mawile again.
It can almost resist his entire move Set. The first attack is always First Impression be sure to use first a X-Defend then heal up afterwards if the health is to low. Then you should be good it can tank some hits and it should go next for Aqua Jet. You did hit it and he will switch it out (Going for his Chandelure for sure if not already dead).
Even if my next tip sounds pretty dumb, but stay in for an sure switch in for your Sharpredo (Night Slash may be requiered to K.O it).
What's left his half dead Golisopod and his Seviper. It should be now easy to finish off the fight.
(This is just a sueggestion since I had kinda the same team around. I can offer you a Aggron I don't really use it anyways and it has 1 Egg Move already, +Attack -Defense)
If you didn' tunlocked the move relearner (the key is in the railnet underground - you can even get there a Aaron - )
Edit: English isn't my main language so sorry if the grammar is not correct.