I can see why it would be annoying, clearly your FIL doesn't have alot going on in his own life to keep busy at the moment!
While I think he is being a bit overbearing, at least you know he is watching out for you all! I mean
IF something were to actually happen (say one day you really do sleep in my mistake), you'd know he'd be there to help and keep a watchful eye on things! I know that is not what you want when all is fine, but I guess I'm trying to say there is a pro to the situation as well!