When a will is probated, it is filed with the court and becomes a public document unless it for some reason is ordered sealed. Filings by the executor, such as an inventory of the estate are also public documents. You may contact the clerk of the probate court where the ex-mother-in-law resided for information on obtaining the file.
Certain assets are transfer on death assets that are not included as part of the probate estate. Assets held in a policy with an insurer or financial institution with a named beneficiary, typically pass outside the probate process. Such assets go to the named beneficiary outside the probate process. If the CD is a transfer on death account, it passes outside the probate process.