Appointee

We had a visit from DWP regarding Appointee regarding my child (ASD) who turns 16 in August and will hopefully be granted PIP (he currently gets DLA). He attends special school (since age 4) is transported to and from school by the local authority and has behavioural issues he is also a people pleaser but has no idea how to handle his affairs and is in denial. As a consequence the DWP lady said that she feels he is able to handle his affairs hence he now has no appointee and I feel that he needs one. How can I appeal this please.

He won't need an appointee until he is 16 in August but we've had the interview and the DWP person actually said to my son Do you know your name address and postcode? the child replied yes. The lady said that's all he needs to know he doesn't lack capacity as if he got lost he knows his name and address so could find his way home!!!! She said he doesn't need an Appointee and I really need to challenge this.