A lot to consider with helping your son to get sober. Has he said he wants to get sober? As long as he’s with this girlfriend enabling his drinking not a chance for his sobriety. From what you’ve said when he was with you & no booze he had to get medical help so sounds like he needs to get professional help to be medically withdrawn from alcohol. You could bring your family together for a intervention but best if you have professional help if you do that to guide your family & have treatment setup prior if your son decides at that time to get help so you can have him enter to get help immediately. Hope your son gets the help he needs & getting into a in-house program would be best for him.