A pro wrestler, huh? Pokedex entries have such an odd way of describing things, but I suppose it can't get any better than Raichu's entry and those Indian elephants. But upon reading it further, it states that Dustox dust isn't flaking wing scales like I had imagined. It's actually
poison (how could I have forgotten it was dual Poison-type!), and if it can bring a pro wrestler asunder, then how about young and susceptible Dylan?
So, there are really four things you could do in this situation:
1) Dylan has to be properly bound up, at a distance, and check that he isn't downwind of attacks with his friend flapping about,
2) Dustox's poison is either not that potent (which could affect the toxicity of other Poison-type attacks, taking on an interesting handicap for the partner) and/or only sheds its powder in small, irritating but not
terrible amounts
3) the poisonous powder is scattered only when Dustox
violently flaps his wings, as opposed to some of it shaking loose constantly from its usual attempt to keep aflutter, or
4) switch out Dustox for the Scatterbug line. I know you personally enjoy Dustox as your favorite Pokemon, but in the same vein as the dusty allergy dynamic you're going for, Scatterbug has a black dust on its body that it can scatter and cause a form of
paralysis (arguably better than being poisoned; you can still move, just very stiffly). Spewpa's powder isn't explained in the Dex to be particularly harmful but it uses it to defend itself, so you can have a freer reign with that, or just relate it back to that paralysis. And Vivillion scatters colorful scales. Since it's role-play, those shed scales don't have to be described as those big square pixel-like patterns, and be more like a finer shedding of color. Just something to consider!
Well, Aromatherapy would be more wisely used as a cure for status conditions. So, if Dylan would absolutely need it to clear the air or as a quick heal from the dangerous effects of the bug's irritants, that would be best than to exhaust his Pokemon for every little thing. That said, it's not to say Dylan
can't abuse Aromatherapy after the first time he discovers it, but his Pokemon would probably become tired and even resentful from the overuse. When Dylan realizes that he's mistreating his Pokemon, he can learn to refrain from using the move until he really needs it. His Pokemon may even see later why he needs it, and jump in on their own from time to time to administer the move when they see fit, you know?
I'm not sure about any charms Dylan could use, but another thought is that he could just lightly spray himself down with Repel constantly to keep his Pokemon at bay. Which is a real shame, but you could always play up that emotional "I love you but you can't get close to me" monologue until a better solution passes by. Tug on some heartstrings, yeah?
... Whew! What a post! And you're absolutely welcome for my little bit of input. I like seeing different types of characters and watching them foster and grow! If you feel like you'd want a little more help with a character or anything else for that matter, feel free to contact me. I'd not mind offering a real world-fantasy blend of opinion for you.
Don't forget to get a good grade! Haha!