There any many ways you can go about defeating this duo! However, it all depends on your team and theirs! We can not provide any tips about the enemy team as you would only see it during a battle.
Neutralizing Gas does work and prevents the ability from working. However, when doing doubles you will be able to see the enemy team and yours. So if they see wheezing they may opt out of it at first or in general and just use their other Pokémon.
Unaware is another great option! As the Dondozo you fight will have it. Making it a neutral stat change battle! Paired with special attack moves you may have a better chance of beating it. Dondozo's has a pretty low special defense so that would be your focus.
High Defense pairs really well as it will most likely not run a special attack as it is pretty set on using physical moves. So getting a wall and hitting it might just work.
Amoongus Clear Smog is the BEST thing for this as unless it runs Terra Steel. It can handle most if not all of its hits with its nice HP stat. Clear Smog would save the day and basically make him a sitting duck. Allowing you to really get a quick set up in especially if you run spore to sleep it and make safe plays!
