@Bettyjo0 Cut and paste the AirBnB Policy below into the messaging system and explain you are not comfortable giving out personal details. He can use the AirBnB email address assigned to you through the reservation.
Pay and communicate on Airbnb
Paying or communicating outside Airbnb makes it harder for us to protect your information and puts you at greater risk of fraud and other security issues. That's why we prohibit paying for a reservation outside our website in our Terms of Service and strongly encourage you to communicate using our messaging system.
Use our messaging system before a booking to confirm details about specific amenities, ask whether other people share the same space, discuss house rules, and talk about the neighborhood. After booking, use it to discuss check-in details.
https://www.airbnb.com/help/article/241/i-m-a-guest--what-are-some-safety-tips-i-can-follow