What can I do if my sibling refuses to turn over our parent’s will?

In Michigan, a person who is a custodian of a will or a person having possession or care of a will must forward it to a probate court in the county where the testator died or owned property with reasonable promptness after the death of a testator. If your sibling refuses to turn over the will to the court or to open probate, you can file a petition with the probate court to compel your sibling to file the will or be found guilty of contempt of court.