Now you are admitting storing guns in a home safe may not classify as secure storage. That's not what you wrote previously. In post #35 of this thread you wrote:
A good gun safe cannot be broken into or picked by a young video game playing psychotic med taking doofus.FYI, the steel plate in most consumer grade gun safes is not very thick. A quality consumer gun safe will have 8 gauge plate which is just 4.37 millimeters thick. The contents of most gun safes can be accessed fairly quickly with an inexpensive circular saw and metal cutting blades by cutting away the roof, or side walls.
For less than $50 at Harbor Freight he could by a circular saw and pack of metal cutting blades. Hearing protection and goggles may push the tab to $50. He also could have dipped into his allowance and bought Harbor Freight's purpose built metal saw for $100 that will cut up to 7mm steel plate.
Assuming the mom had a safe, if he really wanted to get in and knew his mom was going out shopping for 4 hours, he could have quite a surprise waiting for her when she returned home.
A consumer grade safe may be a safer storage spot but it cannot be considered safe storage when a clever but disturbed person has unsupervised access to the house.
Anything he could have done (cameras, print dust, etc) to figure out the combo - she could have done to figure out he was messing with her safe.
I lock my door. Sure someone could just kick down the door - but I still lock it.
However you think it would be best for her to meet her responsibility to make sure her firearms didn't fall into the hands of a psychotic - my point is that she FAILED in that responsibility.