How much house can your buyer afford? Start from their income and debts — or from the monthly payment they're comfortable with — and get a price range with the full payment behind it.
Debts: car, student loans, minimum credit card payments, child support — what shows on a credit report. Not rent, utilities or phone.
A planning estimate, not a pre-approval. Lenders also weigh credit score, reserves and the loan program's rules; VA looks at residual income too. Have your buyer talk to a lender before they shop.