How is Tobias’s son treated in Chapters 52 and 53? What further complications does Tobias encounter in these chapters?

Dr. Hardwick cuts into the baby's infection and pus spills out; he then stitches and dresses the wound. Dr. Hardwick insists on taking the necklace of Elizabeth as collateral for payment; after he departs, Elizabeth tells Tobias that she is pregnant with his baby.