score:8
No, you cannot make this trip at the current time.
Entry from the Schengen area is generally banned, by the proclamation you mentioned. The full text of the proclamation is available here, and lists several exceptions. There's only one exception where a sibling relationship is relevant:
(v) any noncitizen who is the sibling of a U.S. citizen or lawful permanent resident, provided that both are unmarried and under the age of 21;
You said your sibling is 27 and married, so this is not applicable to you. None of the other exceptions appear to be relevant to your situation, based on the information in your question.