MsJames, if i were you i would be seriously, MAJORLY peeved off!
I loathe unannounced visitors at the best of times. And ILs especially! I would have snapped by now for sure! Unless you say something, everyone will assume that it's all perfectly fine with you.
And if ur DF won't talk with you, just go nuts as Maz suggests!
Why on earth are they coming to stay with you now anyways?! Surely at a time like this, they could go to a hotel?
Boys always stand up for their mums, but NOW is when YOU need him to stand up for YOU! It would be part of my worst nightmare to go into labour with my MIL around it doesn't happen!

Hmmm im not sure what u can do... Can you put your foot down with DF and ask that once his friend leaves, u want NO-ONE in your home? It might not be convenient for them, but is there alternate accommodation? Say your Ob has insisted that you should not be under the stress of entertaining overnight guests in this delicate stage.

I totally sympathise with you hun, make sure u look after urself and ur bubby girl first ok? Do whatever it takes to make urself comfortable, and talk it out with DF