Can you provide a specific example from the text where Udi cured a severe physical ailment?

Certainly. Chapter 33 includes a notable account from Hari Sitaram Dixit about a gentleman named Khimji Lalji Joshi, whose daughter was gravely ill. She was so weak that her limbs were like twigs and she could not walk. After being brought to Shirdi, Baba applied Udi to her and blessed her. Remarkably, within a few days, she began to walk on her own. When she still had trouble getting up, Baba gave her a fruit to eat, which resolved her remaining difficulty. This story powerfully illustrates the healing potency of Udi combined with Baba's direct blessing.