My MIL lives abroad, but has been in the UK for the last 2 1/2 months dealing with some family business, though they have been sitting around twiddling their thumbs a lot by their own admittance.
They have made no effort to drive the 3 hour journey to see us - even though we've invited them several times - especially over Christmas when the children were off school and we weren't working. Last night they called to say that they want to stay for 'a night or two' 6 days after our 3rd baby's due! They are tagging seeing us on to travelling to or from a beer festival they want to go to with friends.
We have a small, full house which we're trying to sell. They have a dog, which they expect to stay with us too. On that date I could feasibly be 6 days overdue, actually in labour or have a baby under 2 weeks old. I can't cope with the cooking and cleaning, plus I'm planning a home birth, and the sofa bed in the baby's room is reserved for my mum who will be coming to help with my older two and support me. They've never made an effort to get to know our DCs, so they don't know them at all, and the timing of their visit has nothing to do with wanting to help or wanting to meet the new baby.
So I have said that they can't stay under any circumstances. They are welcome to visit, but they have to in a hotel or B&B (they're loaded). I think that's reasonable, so does DH. They're acting all put out.