arfid and pip

hello , I have a 16 year old son , who is autistic, he has just been diagnosed with ARFID eating disorder, he also has right hemiplegia . Has anyone else filled out the pip form with a child with ARFID?  when he comes to eating and preparing food, he obviously has a eating disorder and literally since the age of 3 only eaten chips ! He wont go near food, he tells my 8 year old daughter that I'm trying to poison her if she is eating anything other then chips ! How would that score on the pip form? just was hoping I may find someone who has similar experiences and has had a reply from pip?