You tell me.
Here's a legal take on the issue:
Negligent Entrustment in Firearm Cases
Negligent entrustment cases are similar to negligent sale cases. In both negligent sale and negligent entrustment cases the crux of the argument is that the defendant was negligent in allowing someone who the defendant knew or had reason to know was incompetent, inexperienced or reckless to have access to the gun.
Entrustment occurs when the gun is given to the person, the person is given permission to use it or the defendant knows that the person will use it without permission.
Courts often combine negligent entrustment with negligent storage because negligent storage is a passive form of negligent entrustment.
Negligent storage involves storing the weapon in such a way that it is likely to be misused.
The usual scenario in such cases is when guns are left accessible to children, particularly small children who do not and cannot be expected to appreciate the danger posed by the weapon.
In negligent storage cases, the theft of the gun does not necessarily relieve the owner of liability if the theft was reasonably foreseeable. In such cases the courts will look at how securely the weapon was stored.
http://injury.findlaw.com/product-liability/product-liability-and-guns.html
Of course, he shot his gun-collecting mom first, so any compensatory damages would have to come from her estate, which probably ain't much.
