a/20369350/1636522

HTML

<div class="qpanel">
    <div class="que">Content for class "que" Goes Here</div>
    <div class="ans">
        <input name="ansr2" type="radio" value="no" />No
    </div>
    <div class="ans">
        <input name="ansr2" type="radio" value="yes" />Yes
        <input disabled="disabled" name="ansr2" type="text" placeholder="If any, give your answer here" />
    </div>
</div>
<div class="qpanel">
    <div class="que">Content for class "que" Goes Here</div>
    <div class="ans">
        <input name="ansr3" type="radio" value="no" />No
    </div>
    <div class="ans">
        <input name="ansr3" type="radio" value="yes" />Yes
        <input disabled="disabled" name="ansr3" type="text" placeholder="If any, give your answer here" />
    </div>
    
    <input disabled="disabled" name="ansr3" type="text" placeholder="If any, give your answer here" />
</div>

JavaScript

$('.qpanel :radio').change(function () {
    // up to ".qpanel", down to the textbox
    var textbox = $(this).closest('.qpanel').find(':text');
    switch ($(this).val()) {
        case 'no': textbox.prop('disabled', true); break;
        case 'yes': textbox.prop('disabled', false); break;
    }
});