He will ask general questions about how is season is going. In detail, he will ask things like: what other schools have contacted you, what schools are you interested in? What are your top schools. How are your grades? Do you wish to sign early?
Some coaches might spend most of the conversation talking about their program and how your sign might fit in.
They are trying to find out as much about his character and intelligence as they can. Also about who their competition is.
Good luck and I hope he gets many calls. They are exciting to get.