Letter of appeal for a denied UK visa

Hi! can you help me with writing a letter of appeal? my brother recently applied for a family tourist visa and was refused. They required him to show evidence of properties and savings, but my brother is a student and we submitted a certification from his university, he is finishing his uni course this march and we wanted him to come over after this, they are now saying that he does not have an education to come back to. I have given them my bank statements and said that they have proven that I can support him on his stay. My brother is just finishing uni and we cannot show any properties on his name and any savings account, this is the reason for my appeal. hoping for your help on this matter

Thank you