I've had better luck with physio and very importantly also a home stretching program. You can try Colin Kroeger at Total Therapy, Metrotown. For home stretching, I would do the ones your physio recommends plus the lower back and sitting stretches.
I bought one from Amazon UK to my grandma. It was really light weight and foldable electric wheelchair. The battery life is good, no complaints. Then I also recommended the same for my friend in Paris for her grandmom, thanks to seller to deliver across EU and UK thru FedEx. It's called Mobiplus X3 electric wheelchair
Mobiplus X3 Electric wheelchair Amazon UK
Mobiplus X3 Fauteuil roulant électrique Amazon FR
PS: this is not affiliate link.
Just a friendly reminder that old school stink bombs are still legal. Just stroll by and discreetly pop a couple of these by their table and your problem is solved.
If you have baseboard heating and no forced air cooling or ventilation, there's nowhere to put a filter. Whoever made the suggestion was probably referring to a portable air purifier like this one.