$('td:last-child a:eq(0)', nRow).remove();
This code will remove the button but I need the button to be shown but to be disabled, the user should not be able to click it.
Use disable property for disabling the button.
Implies your code should be
$('td:last-child a:eq(0)', nRow).prop('disabled', true);
For further reference : HTML Button disable
-Help :)