No, not "nothing," but don't do something foolish in the name of doing "something."
The truth is, there is no way to stop evil people or lunatics from killing lots of people. In the absence of his mother's guns, he could have used fire, an 18-wheeler, homemade explosives, or many, many other means to accomplish his horrific plan.
It is far easier to destroy than to create or protect.
We could, perhaps, reintroduce morality as a prime concept in our country. There is a coldness and hostility between people now that was absent in my childhood. Moral rules are rational -- and foster a sense of humanity that we have lost.