Is travel allowed on visitor visa?

[mak101]

One of my friend is sick and his parents wants to come and take care of him, they already have 10 years visitor visa and travelled to USA before. There are some restrictions on travelling now so wants to get an idea what is the procedure to travel to USA for medical reason.

[rkk09]

Hi,
I think, they must get NIE Approval. On another hand, they may check airlines and check the procedure what they follow these days.
Thanks