I agree with everyone else! I hope your DH will find the backbone to tell them that they need to stay in a hotel. Perhaps he can present it that it will be for their comfort. "You know how babies cry and keep the whole house awake! You'll be
much more comfortable in a hotel. Of course we're going to be exhausted, so it will be great to have you come over during the day; we'll sure be glad to have you here to do laundry, clean the house, fix meals, grocery shop, vacuum..."(and throw them a bone with "hold the baby while we take a shower!") If you come up with a long enough list, they might just postpone their visit. You can hope, anyway.
Personally, I feel that anyone who doesn't plan to wait on YOU shouldn't be visiting in the first month. My ILs came 2 weeks after our son was born (he's 4 weeks now.) They actually stayed in a hotel at first, because there were 7 of them and they couldn't all fit in our guest rooms. They only planned to stay two days, and that was
perfect. But their van broke down, and had to be fixed in town, so 4 of them (2 of the helpful ones!!) drove back in a rental car, and the other 3 moved on over to our house for 3 nights.
I was kind of shocked at the lack of helpfulness. One of the houseguests was DP's mom, and it seemed the only help she was willing to give was holding the baby, as other people have mentioned.

That's really nice, except that he's a brand-new baby who screams if anyone besides me or DP holds him, so I ended up running back to get him anyway. I know I put on a good show of being energetic and 'normal' for a woman with a newborn, but evidently it appeared I didn't need or want any help around the house. Cause they didn't do any laundry (actually I did a load for
them), and they didn't cook any meals (I cooked for them one night, though.)
Mostly they just went sightseeing. I guess DP thinks that they were trying not to inconvenience me, by staying out of the house. But actually being here and helping would have been more welcome. I about died when I discovered that they didn't even strip their beds for me when they left. It seems like that's a natural thing that you'd do as a houseguest any time, and certainly when your hostess has just given birth! I didn't need
more laundry.
It's hard; I
adore DP, and he adores his family. I really want to get along with MIL, and I want her to like me. But now I feel reluctant to play hostess again anytime soon. Trust me, avoid resentment on
your part by having them stay in a hotel.