Right, will try and get down everything I know to make it easier!
My grandson (12) was diagnosed with autisim about april this year after many years of doctors, assessments etc. One of the reasons it took so long was his primary school refused to admit there were any problems and everything was down to my DD's poor parenting skills 
Even when we were officialy told he was autistic at one of the many many meetings that were held in the school with the head teacher, my DD, learning support teacher, educational physcologist, SW, the child pyschatrist doctor fron CAMHS and a couple of other professionals who I cant remember where they were from... the HT afterwards said the she still didnt think DGS was autistic and that the Dr had only said that because she was "under pressure", this is a DR who has years of experience and who said she wasnt under pressure, but she didnt want to give the diognosis at the meeting as she was worried about how DD would take it (it was a relief TBH). She couldnt give the diagnosis earlier as what DGS was showing in tests/assessments and what information DD was giving didnt match what the school was saying!
One more vital bit of info, all the way through primary DGS was bullied by one boy in particular because of his facial tics and this is what leads up to the next bit...
So fast forward to August and DGS started secondary school, they know he's autistic and say he will get all the necessary help etc
A couple of weeks later the boy from primary, once again starts on DGS making fun of his tics, only this time DGS retaliates and they get into a fight and DGS gets excluded (because he threw the first punch and went for him a second time). Anyway DGS gets excluded, nothing happens to other boy AT ALL 
DGS was out of school for about 3 weeks, then allowed back in 3 days a week for 1 HOUR at a time, DD had to take him and collect him, all different times, not easy as she works and has 4 other children (younger) 2 need to get to school, 1 needs picked up (P1 and older sister gets out later) and 2 toddlers, looked after by various family members, so she can get DGS to school, other side of Edinburgh, wait an hour and collect him!
School applied for and got funding for a support worker (sorry dont know the proper term). DGS really likes him and he sits in the class with him and basically keeps an eye on him and helps him when needed.
Anyway he is now in 3 half days, so getting there. On Thursday there was a child planning meeting and the deputy head said he could back full time, starting Monday.
On Friday SW phones DD and tells her that the Head Teacher (who has never attended any meetings or met my DD or DGS) says no he cant go back full time as there is a risk he will kick off again and he they only have the support worker for 15 hours!
He has only ever had this 1 incident in school!
When DD phoned me at work to tell me, I just broke down in tears, I cant beleive they would build his hopes up like this and let him down again 
He's desparate to get back to school, he wants to learn but at this rate it's not going to happen
HT says DGS needs to have his support worker at all times and as they only have funding for 15 hours that's all the education DGS can get, thay wont even agree to let him try without his worker.
If you have read this far, you deserve a medal 
So, is there anything we can do to get the school have him back in full time? I'm probably being emotional and dramatic here but I feel they are discrimanating against him because of his autism, they dont want him there and are doing everything possible to make things hard for him.
There's probably a million things I've missed so feel free to ask questions, I will answer as best I can.