If you are breastfeeding, it is advised against to try to lose all of the baby weight rapidly after delivering, because this can disrupt production, because it is such an energy intensive endeavor. So asking a woman to look exactly the same within three months of delivery, or really at any point during lactation, is totally unreasonable. However, that's not an excuse for packing on so much extra while you are still pregnant, and continuing to gain postpartum. She definitely has a more than an extra twenty in that michelin man bod.