Francesco is a stand up guy and I recommend very highly staying with him. He's a fabulous cook and a generous man. He truly cares. Be sure to take the free tourist bus that stops close to his building. It's a secret that isn't in the guidebooks and will save you time and money getting around to the main sights in the centro historico. Be sure also to get the buzzer name and apartment number from Francesco before arriving to the address, especially if, like me, you have no phone or consistent access to wifi. His neighborhood is close to the Palazzo Reale (Normanni) and in the very colorful Ballaro and Albergero districts: full of markets and authentic Sicilian culture.
Don't think twice. Stay with Francesco. You will not regret it. Your visit to Palermo, and onward through Sicily, with be enhanced.