You can Qt her in the cup, just make sure your parents do a 100% water change every day. If they can get some Aquarium salt at Walmart they can treat her for you. Just premix 1tsp/gal Aq.Salt in a gal of dechlorinated water and leave it out next to her QT cup so it is the same temp. Use that to do water changes. It is definitely easy enough for your parents to do. You can put her (and the jug) on top of the refrigerator to keep her and the new water warm.
After 1 day at 1tsp/gal Aq. Salt, make a new mixture with 2tsp/gal Aquarium Salt and use that for her daily water change. Then make a new mixture at 3tsp/gal the next day and continue using that jug to do water changes for no more than 14 days.