help and advice needed

help much appreciated!!!!

My son is in year six and has a diagnosis of aspergers/adhd I have been into school today to ask what level my son is working at and they gave me a slip as follows:

year 3-reading 3c writing 2a maths 2c

year 4-reading 3b writing 2a maths 3b

year 5-working towards reading 3 writing 2 maths A (have not got a clue what this means)

sorry to be thick-I know he is behind and should be at a level 4 or 5 does this mean he has a learning disability? he does not have a statement and has had for the past year group support with a sen assistant to get him up to a higher level which obviously is not working where do I stand with this as my son struggles so badly in primary school and the school will not help me with the statementing process as they say he is academically bright. I have heard its even harder to get a ECHP plan in secondary school so want to get started as soon as possible to  fight for one if this is the case. Is he at the right level to even take his sats? 

Thankyou very much!