Because you're not attempting to rent the house for a profit, you shouldn't report this arrangement under the Rental Income heading. Continue to deduct your real estate taxes and mortgage interest on the house under Deductions and Credits tab. Report the money he pays you by going to Less Common Income>Miscellaneous Income>Other Reportable Income.
In this situation there is no deduction for the utility payments you made, even though your son is reimbursing you for the utilities. I recommend putting the utilities in his name, or giving him the bills and let him pay them directly.
