Before during and after whelping the bitch needs total privacy and any unwanted visitors should be kept away, otherwise she might react badly and even kill the puppies if she feels threatened. Even though they sleep together now, if he starts to show any interest in them she might panic. Do not let him in with her and the puppies until they are up and about on their feel, not only for the above reasons but for health reasons too, as he will still be going out I presume. The cat might try to get in and sleep in the whelping pen, and could lie on a puppy as they will be very small, so keep it away as well.
Keep the bitch somewhere warm and dark to resemble a 'den' in the wild and keep interruptions to a minimum.
Good luck, and get lots of sleep over the next couple of days, you are going to need it!