Can your DH not reply on FB "didn't realise I imagined calling yesterday, I know you were busy but we did speak before you had to go" or something like that?

Or text back with "cool, we'd love to see you *day*, can you do an hour later? Can you come over? We'd love to see you if you want to see us!" then watch her pull out: I know that people do this to guilt you rather than out of wanting to see you, and she probably can't that day either, just knows you'll say no.

And her mum doesn't know your finances - tell her that isn't true and if she wanted to live with you she could... watch that be pulled away too. If you know it is just a line and she doesn't mean it her refusal will hurt less, especially when she stops saying it.

I know it's a vent, but it annoys me too and finding ways of dealing with it is important as well.