Hi and I am sorry to hear about your son. I have been that child. My parents did everything they could to help me, including four times in inpatient treatment starting at the age of 14 years old. I finally got sober at the age of 47 and I have 7+ years sober now. My parents did not realize that they were enablers although they did the best they could for sure and I was able to make amends to them as well as my brother for the decades of worry. I have posted before, but I lost my partner of 25+ years to alcoholism. I found him deceased. I had to move out of our house when I got sober, but he was still my bond partner and best friend. I had to stay sober and due to him still drinking, I made the difficult decision to move out. I ended up taking him to the ER 6 times in a two year period. He had cirrhosis, pancreatitis, varicies in his esophagus and alcoholic hepatitis. I did everything possible to help him, including getting him into treatment. Ultimately, he just could not stop and it killed him. This has only been a little over a year and I still grieve and miss him terribly. I got his parents and sisters to come down and we had an intervention. His mother, 82, asked him, "I am here to find out where you want to be buried." As harsh as that sounds, I was proud of her. Even that did not stop him. Unfortunately, as an alcoholic, it is only the alcoholic that can make the choice to stop. As painful as it is, refusing to allow him to drink in your home is a boundary you are setting and he is probably miserable not being able to do so. I also would sneak drinks at my parents. The seizures are scary. Another issue that ultimately helped me (besides knowing I was going to die if I did not stop) was the fact that my brother refused to talk to me until I quit. Do you know anyone in AA? Has he been to treatment or AA? If you know someone in AA, it might help to have them come talk to him on one of the weekends he is at your house (and probably physically miserable). As far as the girlfriend, do you have a relationship with her? Does she realize the seriousness of this disease? Being blunt and even sharing with her a story like mine (finding my partner dead) might wake her up although it might not. Have you gone to any al-anon meetings? Taking care of yourself and your pain and sadness is important.
https://al-anon.org/al-anon-meetings/
They have Zoom, phone and in person meetings. These people are in your situation. As painful as it is, I can not change anyone or make anyone do anything, however, I can set boundaries, which it seems like you are. I hope this post has not sounded harsh. It is not meant to be. I can relate to both you and your son, having been in both positions. Feel free to reach out. Take care of you as you are no good to anyone if you don't, especially yourself.