I am sorry but your question is difficult to understand. The attorney normally has nothing to do with non-probate assets. It sounds like these assets had beneficiaries designated, meaning they were not part of the estate at all. That is not the attorney's fault. It is the decedent's fault. It is VERY common for someone to make out a Will providing for a certain distribution of the estate and then structuring their assets in such a way that it totally defeats their supposed intent. It happens ALL the time. The Will does not apply to such assets, except in VERY unusual circumstances.
The attorney normally has nothing to do with designating beneficiaries on assets. The attorney prepares the estate planning documents and then the client does whatever he or she wants to do, almost always without the knowledge or guidance of the attorney.
There is Michigan caselaw that excuses the attorney from liability in cases like this. Of course, there can always be a certain set of facts which might provide a basis for liability. For that reason, you should consult with an attorney of your own to determine if there is any possibility of recovery.
In most counties, even the probate court does not verify the values of assets listed on the inventory.
Finally, if the beneficiaries of the non-probate assets are willing, they can choose to honor the wishes of the decedent, in spite of the fact that the titles were not properly set up.
James Frederick