Seems the key word is "inherited",, BUT by what means? Was it a Form-4 gun passed along as part of an ESTATE distribution to lawful heirs, or was it a "garage job" given to somebody??
If it is a lawful Form-4 gun, you need to find the Form-4 and other relative info to the
deceased's estate to do a Form-5 transfer to a lawful heir through the estates executor/ATF.
The Form-5 will be a "tax-exempt" to the heir (family member able to lawfully own NFA). As of current, only the estates' executor can possess the gun, until it can be lawfully transfered. The best thing to do is call around and find a C2 or C3 in your area and explain the situation and get further advice before a Form-4 gun gets lost and taken out of the system.
If it is a "garage job",, you are S---O---L.
IT IS CONTRABAND!!