Gray Beard is right , it may be better to start with a Class III , Hire them ,and let them talk to BATFE.
ATF lately will give you one story ,then if you call them again you get another.
The Class III will know what paperwork needs to be filed ,and how to go about it.
Be careful ,if he were to pass away the guns are not in his wife's name but in his.
It may be best to have something on file where in that event they are transferred to the Class III ASAP.
This way the guns are still under the deceased mans name ,but not in possession of someone else.
Then they are logged in and accounted for and set up for consignment sale.
If you get some young ATF agent wanting to make a name for himself , he can come in and collect all of those guns ,and arrest everyone there.
You will beat it in court ,but you will not have the guns and the Lawyers will kill you on Legal fees.
This is what my ClassIII and my Lawyer told me.