All the best to you and your boy, Raddy. I went back to re-read some of your earliest posts. It's been a journey.
I can't help much - we are also in the midst of a bullying case. My son is not the primary victim but he's been punched up because he helps the poor kid. What can I say, teachers can be very misguided. Teachers can even be the bully (this was the case for my son at the start of the year. I handled that by going to the principal

after wringing my wrists for 2 mths).
Can you involve the the bully's parent via the school? Surely the mum will not want her son to turn out this way? It's easier said than done I know. Yes the wonderful holidays! Over the months, many things change for young children. Do take care and all the best.