No need to involve him he is a fully grown adult and can contact current school himself if he wants to. Ditto to contacting the LA. I mean has he even spoken to you about high school and apply for places?
My child has an ehcp and gets eotis. Ex has no clue at sll. Is not involved in our life. I stated that in ehcp paperwork and for tribunal I submitted documents to detail his non involvement. They were fine with that.
The local authority could have contacted him but equally it is on him as a parent t to put the effort in to be involved, he clearly hasnt done that.
And as someone who has worked in mainstream and complex needs I am laughing at the naivety of peoold thing the senco will be involved in patents evening or that they would make it clear just how much the child struggles.
The senco sounds inexperienced, she may not even have completed senco training as you can legally be employed as senco without doing so for up to 3 years. Honest many dont know the law around send, many are misled by the LA and pressured also by them.
My sons old sendco tried to tell me he didnt have a speech and communication difficulties and wasnt entitled to any support, he is diagnosed autistic pda, with complex verbal and motor tics, plus other dusabilities. As I work in complex needs I contacted the access to technology speech and language team myself and then they supported so we could access to various things recommended by the Ed psych.
There are some great sendcos, there are many burnt out sendcos beaten by the system and there also some who are clueless as well as some who actively play the LA games. The system is a mess because there is no accountability especially with academy schools.
Op I hope the transition goes smoothly snd he settles and thrives in his new school, well done securing a specialist placement its not easy.