There is nowhere near enough information to give any kind of opinion on the advisability of the BO's plans. Full stop. And not even enough information about the smoke inhalation question the OP has -- (how far away would the horses be? which direction would the wind be blowing? would there be wind? etc etc etc etc).
Your question is - will there be permanent damage to your horse from smoke inhalation. Given that this is unlikely to be an event that is going to go on for weeks, I would imagine that your horse will be absolutely fine. I suspect, like the other poster said, this is just a dreaming sort of "maybe at some time......." sort of statement that she may be making. If the place is nice this would not be something that would even be a concern for me.