Dear Annie,

well, how about teaching your sister how to do it (fill the forms etc), and informing your parents that from now on, she too can do it. If she refuses to learn it, you can blame her for not wanting to help them. Because she is most probably equally intelligent as you, it’s only a matter of will vs laziness (you can mention that too). I think this attitude might give her a headache and she wouldn’t be able escape doing her part of the job any more 😉