I have a friend who has trouble sleeping. Does the Sai Satcharita say anything about Udi helping with insomnia?

The Sai Satcharita does indeed contain accounts of Udi being a remedy for sleep disorders. A footnote in Chapter 33 shares two specific stories. In the first, a man who had been unable to sleep for eight days despite taking a doctor's medicine was given some of Baba's Udi. He took it that evening and reported the next day that he had slept very well throughout the entire night. The second story is about a young child who had not been able to sleep for two months. His father took him to Shirdi for Sai Baba's Darshan, and from that very night, the child's sleep problem was resolved. These narratives from Chapter 33 suggest that with faith, Udi can be a potent aid for those suffering from insomnia.