WPF: Finding text box element before the password field

Code:

---

conditions = new AndCondition(
                                new PropertyCondition(AutomationElement.ControlTypeProperty,
                                                controlType),
                                new PropertyCondition(AutomationElement.IsPasswordProperty, isPassword));

elementWindow.FindFirst(TreeScope.Descendants, conditions);

---

Hello, so I am able to find the password property based on the IsPasswordProperty. How do I find the textbox field right before the password text box? My goal is to find any text box right before password text box is found. How do I step 1 child element down from a found child element?