Hi Yvonne and welcome the forum
I know very little about the Addenbrookes cognitive exam and nothing about how to assess a score. I think your best option would be to talk to the person who gave you the test or your GP. They should be able to explain what it means for your husband.
Was it a Parkinson's UK support worker who helped you with the PIP form? Can you speak to them again? If you don't have contact with your local Parkinson's UK team the helpline people can give you their details. The helpline is on 0808 800 0303.
I hope you get a good result from your PIP application. Please keep posting and let us know how you get on