I can relate to this as my daughter struggled with this all her school life and it wasn’t till after she had her son that we realised what her problem was. Unfortunately he is dyslexic too and struggled just like this boy at school with the same behaviour issues in and out of school. He was unable to write any public exams and left school, but was fortunate to be offered an engineering course at college.
Not sure if this is something that runs in the family line, but my other daughter has since learnt that her 6 year old son is dylexic too.
Fortunately for him it was discovered early on in his school life to get the help he needs from teachers who have an understanding of dyslexia and the support and patience of his parents