In Maryland all wills are filed at the county courthouse. From reading online, that is not necessarily required in Michigan but apparently it has to be signed and witnessed by at least 2 other folks 18+. If she doesn't have one at the probate court, then a deposit box is a good place to look. Has she named an executor?

67 Barracuda FB 69 Superbee "Southern Maryland: If you want a good looking woman, you had better bring her with you"