Neville was still in the loo when Hannah left, looking at himself in the mirror and giving Hannah and his daughter a little privacy before he came out to stand beside her. It wasn't a good time to bring up the baby right now, they had to concentratte on Minerva - getting her home and getting her settled while Neville tried to find out who did this.
He was still seething inside and fiddling with his thumbnail anxiously when Hannah asked how it all happened. "Minnie was worried about one of her friends and went out to have a drink, get her mind off of it. She ended up meeting someone and went away from the club with them. Next thing she remembers a Hit Wizard found her in Diagon Alley and he brought her here." All the while, Neville had one hand on his wife's shoulder, possibly to steady himself. But he needed steadying.