I'm not a doctor, but after some light googling, i'm almost 100% certain that charcoal doesn't work for inhaled poisons.

idgaf about a throwaway I used to ask r/crustpunk for band recs, want me to give you the creds?

I'd say that there's the assumption that she went to the vet and said "I tried to gas my dogs last night and now they aren't walking around" or "I accidentally left the gas on and poisoned my dogs" when she might have just said she found her dogs this way, which is much more likely.

With urgent medical treatment like this vets would have a protocol. Dogs are ridiculous for eating things that cause self-termination and it happens all the time. If you have two dogs presenting with an inability to walk then immediately the vet is going to ask "Wtf did they eat??".

When it comes to medical interventions like this in an urgent setting, I'd hazard a guess that charcoal is routinely administered. If there's any toxin in their digestive tract then it's the best chance of adsorbing it. Activated charcoal will adsorb orally administered medications too but you can hook a dog up to an IV so they can mainline any meds and even if there's a remote chance they ate something bad, charcoal is very cheap and very safe to administer especially if you're only doing it occasionally.

If a vet told me that as a matter of routine whenever a dog presents with any kind of poisoning symptoms, they administer charcoal I'd absolutely believe it. Same goes for doctors in an emergency setting working with young kids and people with intellectual disability.