Keeping in mind that taxes vary from locale to locale...

I think he's got a basic idea of how much it's going to cost, and at this point he needs to see a mortgage lender, in person, to work out the details. They've got much more detailed worksheets that take all the subtle details like taxes into account. They can give lots of advice regarding things like how to work the down payment, how an appraisal works into the value of the loan, how your credit record can change the type of loan you get, etc.

(This is what my wife does for a living, by the way)