I'm having trouble sleeping. Is there anything in the Sai Satcharita about Udi helping with sleep issues?

Yes, Chapter 33 of the Sai Satcharita contains accounts where Udi provided relief from sleeplessness. R. Hari Sitaram Dixit recounts the story of his friend who came to him after suffering from insomnia for eight days, finding no relief from a doctor's medicine. Dixit gave him Maharaj's Udi and told him to take it. The very next day, the friend reported that he had slept very well throughout the night after taking the Udi. A similar instance involved a friend's child in Bandra who had not slept for two months but began sleeping soundly every night after being taken to Shirdi for Darshan.