Brother Unstable behaviour post breakup.

Hello My brother since last two months is showing extremely erractic behaviour. He is unable to stay at home at night and feels his thoughts are not in his control. He had been consuming alcohol for about a year of so but this sudden change in his behaviour has come about after his breakup. He keeps wandering outside home at night and stands in the road alone. Cries at night and speaks random things that doesn't make sense. Keeps talking about the breakup feels guilty of his mistakes feels guilty of his behaviour that he is letting down everyone. I had recently consulted a psychiatrist and started his medication as mentioned but he says he is feeling worse with the medication. He feels like he is forgetting everything and sense of vomiting prevails. He is not getting better and every night is facing the same thing. We are clueless how to help him and what's wrong with him. During the day he realises that he is not behaving well and he should not roam around at night but again same.