Upvote:3
Is there any restrictions on the accompanying persons? First degree family members only? siblings? friends?
Yes! the visa is issued for ONE person only. The accompanying persons need to apply for the same visa as well.
There is no mention of how many persons are allowed to apply for this visa. If the documents and the financial status are good, I guess there will be no problem. However, they can always apply for a normal Schengen visa.
Source: https://www.schengenvisainfo.com/schengen-medical-visa/