Is there anyway to repo a car without reporting it stolen if your sibling has the car and is not making payments on it?

If the sibling has the car with permission, you CANT report it stolen. If you are listed on the TITLE as owner or co-owner, go get the car. If you are listed as leinholder, have some type of proof that sibling is in DEFAULT of a loan using the car as collateral, go get it or hire a repo agency to get it.