So I disagree that the OP has no obligation whatsoever. I agree that the husband should be cleaning for his family, but I also recognise that is not how all house holds work*.
However, I strongly feel that a welcomed guest should be accorded appropriate hospitality. I also believe that all guests are welcomed guests as a potential host should be completely free to say "No" to any guest that they do not wish to host. Grudging hospitality is completely unfair to both guest and host. So, once someone is allowed into your home they should get a welcome bit of hospitality.
If it's short notice, things may be slightly more disorganised, but I don't think there should be any "punishing of the guest".
This is a tricky one as the husband Ok'd the change in plans but the wife seems to feel responsible for cleaning. But husband and wife should be on the same page as to guests and flexibility and it shouldn't be the guest who bears the brunt of that miscommunication.
All that been said, I don't have a lot of sympathy for a guest that says nasty things about housekeeping.
*minor off topic: We have a cleaning person who comes every two weeks to scrub things for about 2 hours. I loves it. I was away for several months that the cleaning person was unaware of. After I was back for a couple months the cleaning person commented to my husband that "Your wife must be away. The house is much messier" My husband simply didn't have the heart to explain that the oppisite was true.
I love the replies of all the PP's but I do agree with everything Deetee said here. If OP doesn't draw a line on the change of plans then according her the hospitality she'd give becomes an obligation.
OP, get your hubby on board, if possible to do the cleaning up to your standards as best as you both have time for. If you can afford it, a cleaning service will be a good idea for the doing the rough work.
Then direct all snarky comments to your DH (her son!) and bean dip.
My mom's MIL used to make all kinds of comments on my mom's laid back cleaning style (my mom doesn't dust, do laundry or vacuum - IF it gets done, it's all done by my dad). So my mom's MIL (my grandmother) would request to visit for anywhere from 2 weeks to 2 months in the wintertime. It drove my dad nuts cuz he didn't really like his mother. My mom didn't care because she could easily ignore her MIL and loved having someone else do her cleaning and some light cooking.
OT: Deetee, maybe my brain's not working right. In your last paragraph it sounds like you're saying that your DH does the cleaning. Why did your cleaning person think the house was messier, not knowing you're away? I'm all confused!