If he was in Rehab for 90 days and just got out and "had some beers", then prepare for the worst. He is not doing good and his head is not in the right place. I am not saying that it is possible to be addicted to only one substance and to be able to do others, but any kind of rehab he had would have for 90 days likely told him each day that he should not drink either. I wish both of you the best.