My breastfeeding wife with a 5 day old newborn is overproducing milk. her breasts are engorged with milk and they hurt, sometimes leak. what can we do?

Use pump store milk: Use pump to store milk in frig. However see a health care professional to figure this out; It could be a Hormonal imbalance problem that needs to be diagnosed and treated;

Pump and store: If the baby is not keeping up with your supply, simply empty the breasts after feeding with a manual or electric pump to relieve symptoms and to prevent mastitis. You can freeze and store all your extra milk when you are not able to breast feed or are ill and cannot breastfeed