Sibling petitions will take about 14-16 years until the visa is available.

It is possible that a denial or more information could be requested as a result.

Refer to the visa bulletin with your priority date to determine when visa will become available.

The service center does not matter as the visa bulletin determines wait times.

The intent of the adult child can infer the intent of the applicant parent.

By departing the US she abandoned her application.

It will likely not be rejected for this.

May be better to refile after 5 years post incident.

Yes a third party may pay the NVC fees.

Yes this is possible even if you were not original sponsor.