Help my nephew please

Famandha secondary school at mopani District Nsami, I have a consern in my nephew's future he's repeating grade 11 for the third time, I went to the school and I talk to the class teacher about the issues he explained to me that he tried to speak with the acting Principal Mabasa but he refuse to promote my nephew, class teacher referred me to the principal office, i went there and talk to the principal, only to find out that my nephew was cheating in exam in 2019 but what I was asking to him to promote my nephew to go to next grade before he drop out, principal send me to Nsami District, they just tell me that they don't have powers to promote only school can do that and they will support them in there decision so I went back to the principal to tell him feedback from department of education, principal refused to promote him because of he was cheating in exam 2019,end he forced my nephew to change the subject