Hi, my name is Dunkley! Any advice on winning a PIP appeal?

Hi I'm a support worker with the local mental health team , Horace has schizophrenia and mental health problems ( Horace has given me consent to speak on his behalf ) he was turned down for PIP and is now waiting for a date for his tribunal . He scored 0 on most of his assessment so yes he can do physical things like washing and dressing etc but he struggles with engaging in ever day life . He has very little contact with the outside world and his family .I have several patients in this situation . The assessment feels a bit unfair . Horace is now struggling financially I'm bringing him weekly food parcels and I've just brought him clothing and toiletries. If anyone has any advice on the best way to try and win his appeal we would both really appreciate it . 
Many thanks Claire ?