How do I disable swipe to unlock on iPhone 4 iOS 7.1.2

Is it possible to disable or switch off swipe to unlock (the screen) on iPhone 4, iOS 7.1.2. I am not interested in pass codes etc. only the swipe to unlock. I am trying to help my mother, who is over 80 and simplify her life. She is at home all the time and does not need to protect her privacy or information therefore this iphone function is only delaying her to make calls.

Thank you.