My friend has been suffering from insomnia. Are there any accounts in the Sai Satcharita where Udi has helped with sleep problems?

Yes, Chapter 33 of the Shri Sai Satcharita provides specific examples of Udi's power to remedy sleep issues. In a footnote, Hari Sitaram Dixit shares two such accounts. In one case, his friend had been unable to sleep for eight days, and doctors' medicines were ineffective. After being given Maharaj's Udi, as per the account in Chapter 33, the friend slept very well that same night. A similar story is told of another friend's child from Bandra who had not been able to sleep for two months; a trip to Shirdi for Maharaj's Darshan resolved the issue, and the child began to sleep soundly every night.