Okay, using the "No Answer" survey setting simplifies things a bit and to expand a little on your line of thinking...
Code:
<script type="text/javascript" charset="utf-8">
$(document).ready(function() {
// Identify the questions
var thisQuestion = $('#question'+{QID}+'');
var nextQuestion = $(thisQuestion).nextAll('.text-short:eq(0)');
// Hide the short-text question
$(nextQuestion).hide();
// Move the hidden text input into the array
$('th.answertext:last', thisQuestion).append($('input[type="text"]', nextQuestion)).closest('tr').addClass('otherRow');
// Some styling...
$('input[type="text"]', thisQuestion).css({
'width': '50%'
});
// Handle the "Other" radios
$('input[type="text"]', thisQuestion).on('keyup change',function(event){
event.stopPropagation();
if($.trim($(this).val()) == '') {
$('.otherRow input:radio[value!=""]', thisQuestion).prop('checked',false);
$('.otherRow input:radio[value=""]', thisQuestion).click();
}
else {
$('.otherRow input:radio[value=""]', thisQuestion).prop('checked',false);
}
});
// Handle the "Other" text input
$('.otherRow input.radio', thisQuestion).on('click',function(event){
if($(this).attr('value') == '') {
$('.otherRow input[type="text"]', thisQuestion).val('');
}
});
// Validate the "Other" text input(s) on submit
if($('#movenextbtn, #movesubmitbtn').attr('data-inserted-other') != 'true') { // We're only doing this once on this page
$('#movenextbtn, #movesubmitbtn').attr('data-inserted-other', 'true').on('click.insertedOther', function (event) {
var otherError = 0;
$('.array-flexible-row .otherRow').each(function(i) {
if(($('input:radio[value!=""]:checked', this).length > 0 && $('input[type="text"]', this).val() == '') || ($('input:radio[value!=""]:checked', this).length == 0 && $('input[type="text"]', this).val() != '')) {
otherError = 1;
}
});
if(otherError == 1) {
alert('Please review your answer in the "Other" row(s).');
return false;
}
});
}
});
</script>
. I have a suggestion in your code. Please append an error below below question text and do not let user to continue (return false on submit) if user try to pass question leaving textbox empty and choosing a radio button in the same row or vice versa. 
