The focus of a qml item can be changed although enabled option of the qml item is set as false.

import QtQuick 2.3
import QtQuick.Window 2.2

Window {
    visible: true
    width: 500
    height: 500
    
    MouseArea {
        anchors.fill: parent
        onPressed: {
            console.warn("mouse is pressed")
            rect3.enabled = false;
            rect3.forceActiveFocus();
        }
        
        onReleased: {
            console.warn("mouse is released")
        }
        
        onPressAndHold: {
            console.warn("mouse is pressAndHold")
            rect3.enabled = true;
        }
    }
    
    Rectangle {
        id: rect1
        width: 100
        height: 100
        color: "red"
        focus: true
        
        onFocusChanged: {
            console.warn("rect1 focus is changed as " + focus);
        }
        
        onActiveFocusChanged: {
            console.warn("rect1 active focus is changed as " + activeFocus);
        }

        Keys.onPressed: {
            console.warn("key " + event.key + " is pressed at rect1");
        }
    }
    
    Rectangle {
        id: rect2
        anchors.left: rect1.right
        anchors.leftMargin: 50
        width: 100
        height: 100
        color: "blue"
        
        onFocusChanged: {
            console.warn("rect2 focus is changed as " + focus);
        }
        
        onActiveFocusChanged: {
            console.warn("rect2 active focus is changed as " + activeFocus);
        }

        Keys.onPressed: {
            console.warn("key " + event.key + " is pressed at rect2");
        }
        
        onEnabledChanged: {
            console.warn("rect2 enabled is " + enabled);
        }
        
        Rectangle {
            id: rect3
            width: 50
            height: 50
            color: "black"
            
            onFocusChanged: {
                console.warn("rect3 focus is changed as " + focus);
            }
            
            onActiveFocusChanged: {
                console.warn("rect3 active focus is changed as " + activeFocus);
            }

            Keys.onPressed: {
                console.warn("key " + event.key + " is pressed at rect3");
            }
            
            onEnabledChanged: {
                console.warn("rect3 enabled is " + enabled);
            }
        }
    }
}

qml: rect3 enabled is false
qml: rect3 focus is changed as true