So apparently after month five of a pregnancy, women start “nesting”, which is an uncontrollable urge to clean the home and prepare for the baby’s arrival. Your mother has very much developed this instinct. This is her nesting in action.
Your grandmother would think it’s because I can’t cook and so your mother needs to prepare tubs of food and vats of soup, and then freezing them for meals to be eaten after you’ve arrived. She might be right. Still doesn’t change the fact your mother ordered about 20 kilos of bones/carcasses and turned our flat into a soup kitchen (you may only see a picture with three pots, but those three pots were used multiple times)!