Hi Patric,

You can do this on PHP as well as JS side. I wrote little function that you can add to your theme function.php file like in this tutorial and which will allows you to specify column numbers that you do not want to be sortable as well as table id on which you want to apply this:

function sortColDisable( $object, $table_id ) {
   if ( $table_id == 37 ) {
      $object->dataTableParams->columnDefs[3]->bSortable = false;
      $object->dataTableParams->columnDefs[4]->bSortable = false;
   }
   return $object;
}
add_filter('wpdatatables_filter_table_description', 'sortColDisable', 10, 2);

In this example it will disable sorting on columns 3 and 4 for table with id 37

Please be aware that numbering is zero based (so first column would be 0) and it counts hidden columns as well