Alcohol and antidepressants aren't a great mix, but I think if you were going to see any serious side effects you'd have seen them by now.
The alcohol is a much greater threat to his health. That volume of alcohol will trash his liver and affect his brain in time.
It's a pity your doctor didn't know about the alcohol dependency, as it's quite possible that the depression/anxiety is just caused by the alcohol. Citalopram would be unlikely to help alcohol-associated depression/anxiety much.
it is dangerous to mix alcohol and anti depressants, he really needs to cut down the beer as it will seriously damage his organs, get him help
He's self-medicating and taking prescription meds as well, a horrible mix. Although he has gotten by with mixing the two thus far, all it can take is one extra drink. I had a friend who did this on a regular basis, one morning she just didn't wake up. They assumed she consumed more alcohol than usual the night before. The alcohol is slowing killing him and leading him down a very slippery slope. He needs to address his problems with a therapist and he needs to want to stop drinking and get into AA. I know it's difficult for you to stand by and watch this, so I hope you can convince him to get help. I wish you all the best with this and take care.
Risk of liver failure and worsened depression.
M4