Is a letter from my mother and proof of diagnoses enough?

I have already been awarded PIP and I’m currently going thru a change of circumstances.

My mother is my carer and she has written and signed a 4 page long letter about my how my disabilities affect me and how she helps me. I have submitted this letter and a patient summary and my blue badge number to PIP, will this be enough evidence? They have said I still need to do an assessment but I just wanna make sure I’ve given enough evidence.

Edit: I’ve also written my own letter following the structure given by citizens advice on what to write, and sent in GP consultation notes where I’ve been complaining to the doctor about my issues long before I submitted a change in circumstances.