You can file, and process all paperwork till interview. However visa interview cannot be scheduled till ban is lifted.

Thanks.

Is it easier to get green card for parents in USA as compared to Nepal? Just wondering from perspective of consulars and difficulty in getting visas in Nepal.

Sponsoring parents when they are in states is lot easier. Time line- sponsored by citizen:
Applied I-130 and I485 concurrently on April approved and GC delivered by October.

Best of luck

What kind of medical help the parents can receive? Do they get medicade or Medicare?