Имитация нажатия на радио кнопку при нажатии на другое поле

var input = document.getElementsByClassName('input')[0], 
  inputRadio = document.getElementsByClassName('input_radio'); 
 
input.addEventListener('focus', () => { 
  inputRadio[1].checked = 1; 
}) 
 
input.addEventListener('blur', () => { 
  if (input.value == '') { 
    inputRadio[0].checked = 1; 
  } 
})

<div id="some" class="some"> 
  <label for="some">Заголовок</label> 
  <p> 
    <label> 
           <input type="radio" class="input_radio" name="some_radio"  
           checked="checked" />	 
           <span class="radio-custom"></span> 
    	   <span class="label">Выбрать 0</span> 
    	</label> 
  </p> 
  <p> 
    <label> 
        <input type="radio" class="input_radio" name="some_radio"/>  
    	<span class="radio-custom"></span> 
    	<span class="label">Выбрать 1 </span> 
        <input type="text" class="input" name="price" value=""> 
    </label> 
  </p> 
</div>