Will GBH section 18 and ABH be a custodial sentence in UK?

My brother has just finished a night shift (6am) and went to a shop to buy packet of cigerettes. He had brought the cigerettes as the man gave him back the change, his istant told him no smoking in shop to which my brother showed that his hand was outside. The shop isat called him a racial remark in his language which my brother understood. My brother clarified if he was talking to him to which he replied yes. My brother left and came back with a hammer. A fight broke out, police called and brother charged with ABH on 1and GBH on the other.. Only cuts and bruises to all parties involved. He appeared in Magistrate Court 19th July, pleaded guilty and conditional bail (stay at sisters house) to appear in Crown Courth 28th July. What is the likely outcome bearing in mind he has no previous convictions other than Criminal damage 1987 and carrying an offensive weapon 1988 (worked as a butcher and mum gave him knife to sharpen for her at his workplace - fined for this offence.)