My in laws are coming to visit for Christmas. My FIL has alot of allergies and severe asthma. He's allergic to cats but he's developed a bit of a tolerance to them. They actually have a couple cats at their house and they don't bother him anymore due to the exposure. He does have a little more trouble with cats that he isn't used to. I have two shorthairs who are pretty bad shedders.

Last time he was at our house he did okay, but they had a hotel room. This time they are staying with us. He says not to worry about him, but of course I will because he has had life threatening asthma attacks before.

What do I do to lessen the irritants? I heard sweeping and vacuuming can make it worse because it stirs up the dander. Is this true? Or is it a myth? I have a month or so to prepare, so any suggestions would be greatly appreciated.

Also, he's allergic to dust (and we have all hardwood floors... hard to keep the dust gone) and should I make sure to have filters changed and all that?

If your vaccum is not a HEPA vac, then it will stir things up a bit. But as long as you dust and vaccumm really well a least a few hours before they visit, then everything will be settled back down it it will help him overall. I would definitely change furnace filters. In fact if you get a 3-M filtrete filter, it will help clean the air in your home a lot. You might find even after he leaves that you still like the filters, as they cut down on household dust a lot.

it is actually not the dander that most people with cat/dog allergies are allergic to, it is the saliva. Naturally since a cat licks itself the saliva is on the hair etc. It does help to vacuum and also to brush the cats and/or bathe them. THey also sell at the store those waterless bath wipes you can wipe down your animals with (they are basically like baby wipes). Of course if you can make one room where the cats cannot go while your FIL is there so he can stay in there that will help too.