I agree with everyone, don't wake him. She should enjoy the sleep cause he is only a couple weeks old and his sleep patterns could change quickly.
I stopped waking my son after the first week since he gained his birth weight back in less than a week. If she gets him in a routine now, does the dream feed, I would let him sleep until whenever he wakes up, even if that means him sleeping longer than 5 hours. I wouldn't set the alarm and wake him up. I think the more you wake him up to feed, the more it could create a habit of him waking and will need to be fixed later on.
Good Luck!