What was Sai Baba's specific response and instruction when the parents of the suffering child approached him?

When the parents of the child with the bone-cyst approached Sai Baba, they were in great distress. Chapter 34 describes them pleading with choked voices and pitiful faces, explaining how exhausted they were from seeing their son's suffering. Sai, described as the embodiment of compassion, immediately reassured them. He told them to be worry-free and made a profound promise that those who seek shelter in his Masjid shall never face downfall. His specific instruction was to take the Udi he provided and smear it on the boy's wound, thus offering them both spiritual assurance and a tangible, divine remedy for their child's ailment.