Yikes! This sounds so dangerous. Aren't you afraid that you may one day walk in and have one of those guns accidentally go off while pointed at you?
I think you should confront him (when he's sober), and make sure he has no way of accessing the guns again. But why should you have to get the guns out of the house if they are something you enjoy and know how to use responsibly? Maybe the guns could stay, and he could leave? JMHO