Natural ways to help asthmatics?
no carpeting in the house, it traps dust and molds.
curtains and blankets and such that can be washed, and are fairly frequently, in hot water to kill the dust mites.
no stuffed animals in the beds, or rooms probably. When I was a kid, Mom and Dad shaved our stuffed animals, partly to cut down on the dust issue, partly because pulling the fuzz leads to hairballs.
tightly woven covers for pillows and mattresses to keep dust mites away from the person.
a good air cleaning furnace and air conditioning system with filters frequently changed. We've got ours set so the fan is always moving the air whether it's being actively heated or cooled. Seems to have helped.
get rid of all scented personal care products. go with unscented. This is an allergy issue as far as I can tell. Allergy to a common inexpensive perfume base, orris root, is common and easily avoided by losing the perfumed products. Same goes for room fresheners and all that rot.
During pollen seasons: spring and fall, keep windows closed to keep the pollens out.
The allergic person does not mow the lawn.
FWIW the allergic person shouldn't be the one running the vacuum either.
No pets with fur or feathers. This one sucks.
Don't put carpeting on concrete floors, mold trap that....but you've already BTDT