I'm in agreement with everyone else - I'd pull the plug on the Intervention and focus on educating myself about addiction to clarify exactly what I was dealing with here. Rushing too quickly into your next steps could equate to an escalation in his anger/violence & use when he finds out. It's important to understand for instance, that his video game addiction & alcohol addiction ARE related, not separate issues they way it may seem on the surface.
Addiction is so much more than the person's drug of choice - in fact, it's hardly ever about the substance itself & always about finding ways to numb ourselves away from the realities & stresses of life. Many people suffer cross addictions - alcohol, drugs, sex, food, gambling, gaming, workaholism.... it all stems from the same basic dysfunction.
Interventions also rely heavily on the participants' willingness to follow through with whatever tough-love approach they agree on ahead of time. If it's something you are determined to go through with, make sure you understand what boundaries you intend to verbalize ahead of time, make sure you are READY to do what you say & walk your talk. If there are no boundaries or ultimatums issued during the Intervention then it's just a discussion, not an intervention at all. Are you prepared to insist on a specific course of treatment or recommend a facility or program for him to start immediately? It's important to know ahead of time what your expectations around all of this are & exactly what your Plan B is for if/when he doesn't see it the same way. Do you just go back to the same ole, same ole? Are you willing to move out until he's ready to commit to sobriety? Logistically, interventions have a very low long-term success rate from everything that I've read. I would really, really suggest not wasting your time.