Obsessional slowness with eating

Hello

My 24-year-old son has Aspergers, Dyspraxia and OCD.

He had a breakdown at primary school and developed OCD at that time. He has various issues but the most problematic is around his eating.

As an example:

Last night he could not finish eating his tea (which he started at around 7pm) until 4AM !!!

We have been going round in circles trying to get help with no success. He was referred for mainstream CBT but cannot verbally express what the issue is to people so that did not help at all.

My question is:

Is there a category of person that could help in this area - and how do we get in touch with them?

Many thanks

Graeme