I heard Damu Anna had a personal problem that Sai Baba helped him with. What was it?

Yes, the source material highlights how Sai Baba wards off the misfortunes of his devotees. In Chapter 25, it is mentioned that Damu Anna had a significant personal struggle: despite having two wives, he had no children. This caused him distress, but through his devotion and by receiving Sai Baba's divine blessings, he was eventually blessed with the birth of sons. This particular story is presented as a testament to Sai's grace and ability to grant the desired objects of his followers and remove their suffering, showing how the Guru-Mother is an "Ocean of Mercy."