I am pretty sure that he should have some kind of support in place if he is indeed a prader willi syndrome sufferer as he is actually not able to take responsibility for his own actions with regards to food and his health care specialists would know this.
This is from the PWS website so that people can have an idea of what this syndrome is and understand why this guy really cant be solely responsible for his size if there is noone there to monitor his intake:
Most people with PWS have borderline or moderate learning difficulties. Some
people have recorded IQs of 90 or above, whilst a minority have severe learning difficulties. The average IQ is around 70 or slightly lower, although individuals may sometimes find it difficult to perform at their IQ level, as emotional and social skills are often less developed. Reading and writing skills are usually considerably better than number skills and abstract thinking. Individuals often excel at sedentary activities such as jigsaw puzzles, "wordsearches", sewing, drawing and colouring.
http://pwsa.co.uk/main.php?catagory=1
He will probably really think that it is the council that have made him fat as he could well be unable to understand that it is his own actions making him this size.
I feel for the guy I really do and I wonder who is providing his care on a day to day basis as he obviously needs it. Whoever it is needs a huge kick up the backside!