Worried Asperger's son p.i.p interview

Hi,
My son is 22 , has Asperger's and suffers from anxiety and depression.He does not go out but has been accompanied to the local boxing gym on a handful of occasions as it is his new obsession. It was really small and social interaction as you can imagine is at a bare minimum as people train themselves. Apart from this he does not go out at all.
I am now worried this will go against him in his pip as their "proof "of being able to go out and handle stressful situations/ communicate without support.Although this is far from the truth.His high anxiety meeting new people has resulted in him just going to the doctor's and visiting his grandmother, always accompanied. He has a punchbag at home and the repetition of movement helps him calm down.
Any advice regarding this for his interview would be appreciated.
I will be attending with him and do not want this information to be misconstrued into something it isn't.
I do predict he will not talk much as the stress over this interview is already starting to show, something I warned pip would happen.

My son is similar and I gave examples of what he was unable to do, such as go out and meet people, make friends, have a social life and all the different situations where he needed communication support and social support as well as being unable to go to places on his own. The face to face itself can work to your advantage if it shows how difficult your son finds it to communicate, I had to either clarify or answer entirely on my son's behalf for most of the questions asked because he stared at the floor and gave one word answers or shrugged his shoulders. I also emphasised that he needed travel training to go somewhere on his own which can take weeks for him to build up a template in his head and that he was unable to just go out whenever he felt like it due to his anxiety, getting lost, having difficulties with others etc. Does just going to boxing and to his grandmothers mean he can reliably mix with others, communicate reliably and find his way on unfamiliar routes whenever he needs to? To my mind it doesn't. Think of all the things he can't do and the places he feels unable to go to because of his Aspergers, the reasons for this and the kinds of help he needs and relate it to the PIP criteria, we managed to put together quite a long list and used some as examples, not only on the form, but also during the face to face. You need to give enough of the right kind of info so they don't make incorrect assumptions. Best of luck.