"She should be more worried about the extra dust
The smell is a sort of slightly sweet smell, not at all unpleasant IME, and not like an open fire. There is no smoke etc. from my wood boiler (it has a flue-bypass mode when you open the door, e.g. to re-fill it, so that it creates a strong draft and nothing comes out of the boiler door - also very helpful when lighting it as the positive air flow creates a roaring blaze in no time!).
From a wood burning stove there will be some smoke / burning smell when you open the doors to top it up. Any smoke blowing back into the house is annoying, of course, but the burning smell is quite pleasant IME - it doesn't smell like the place is burning down, or a pot has been left on the stove too long.