In a family situation, all ablebodied persons old enough to be trusted with breakables *should* be pitching in according to their ability and thinking more about "what can I contribute" than "what can I get away without doing?" If that is not happening, there could be
1) a communication/maturity issue - one person does all the work and seethes silently, while the others immaturely assume magic fairies have done it.
2) a character/relationship issue - some family members feel entitled to be waited on, see the disparity and are selfishly exploiting it.
Depending on your relationships, you may be able to carry off requesting/instructing others to do certain tasks. Personally, I would not be comfortable instructing my nieces and nephews - but then, their parents do so, so it has never come up. If you are dealing with Scenario 1, a simple request of "hey, everybody - let's get this place cleaned up so Mom and Dad can relax" should help get them started, so you can discuss the division of labor among yourselves.
If you have scenario 2 and your relatives are such baconfed knaves that the request is ignored or taken as an insult, then you must make your decision on whether you are willing to do the work, or leave it for your parents. In situations like that, the burden usually falls on the one who cares most. Just to warn you, if that is the type of person you dealing with, holiday dinner is just the tip of the iceberg. Just wait till Mom and Dad need long-term care. Again, the burden falls on the one who cares most. It may be more productive to polish your communication skills now, and if there is no improvement I like TinkyTinky's suggestions.
Actually, I also thought of a third scenario I have encountered:
3) One person sets themselves up as a perfectionistic martyr (PM), and every task must be done according to that person's idea of the perfect time/place/manner. Any deviation from said perfect ideal is harshly criticized, either directly or with sighs, grumbling, pointed looks or passive-aggressive comments. Everyone else has made the rational decision to leave PM to their own devices.
I am assuming, OP, that you are not creating a PM scenario, but it is always worth it to "check yourself" first.
In any event, I think a "cards on the table" discussion with your sibling is in order.