DLA to PIP

My husband is being processed from DLA to PIP. it is on mental health grounds. The issue we have is medical evidence. He did have a cpn and counselling before we married. We had to move to a new area when we married. I am an ex nurse and along with his GP we dealt with him without involving mental health services. My health has deteriorated and I have mobility issues, so we have had to move again into a bungalow. Since moving he has managed to visit the doctor cos he had to to get his medication, but I always have to go with him. He rarely leaves the house as his anxiety is very high. The issue is because I deal with him we have not needed mental health intervention. He is ok, with me but if things go wrong I am there to help him. He can make a coffee for example but if he spills the milk then he is overwhelmed by anxiety leading to a panic attack. I talk him throught this. He has been called for a f2f but I rang and requested a home visit, which atos have processed so we a waiting to see if we get that. In just getting the letter he has began self harming (headbanging scratching till bleading), I am worried because in the last 6 years we have had only myself and his old gp (who has retired) that know him. How can we provided evidence? He has been on Dla for 7 years now.

Thank you Gordon, I did fill out the PIP form in detail as you suggested. I will make an appointment with his GP and see what they have available.