First of all, get the gun out of the house. He could have killed somebody--you, himself, a neighborhood kid--running around drunk with a loaded gun.
Maybe this will have shaken him up to the point where he realizes he must quit drinking. Typically, though, alcoholics first need to try to "control" their drinking. This never works. He may "control" it for a short period of time, but it won't last long. In addition, if he is shaking, he is going through withdrawal on a daily basis and really should undergo medically supervised detox. Otherwise, quitting drinking is likely to be extremely painful, if not dangerous.
See if he will agree to go to detox followed by an intensive outpatient treatment program, or AA. AA will send someone over to talk with him if he is willing to listen. You can call the number in the book. Usually a recovered alcoholic has the best chance of getting through the denial surrounding the disease.
Good luck. Have you decided what you are going to do if he refuses? Don't make any threats or ultimatums unless you are SURE you are willing to carry them out. And regardless of what else you do, or what he does, I hope you will get yourself to Al-Anon.