I live with my partner of 16 years and her 18 year old son. He was abandoned by his biological father before he was born. My partner left him in the Philippines when she came to work in the UK. He came to the UK at the age of five. He has two older sisters, aged 24 and 26, who have left home and were no problem whatsoever.
He has just finished his college course and will go to Uni in the autumn. He will not speak to us, spends his whole life in his room in the dark. He has an extraordinarily restricted diet of crap and refuses to try any new foods. He agrees that he needs to get some sort of holiday job, but steadfastly avoids doing anything about it. He has never in his life called his mother Mum, Mummy, or anything at all. Oddly enough, he does call me Dad.
He has no friends or interests (other than computer games - there's a surprise) and takes no exercise. He is incredibly weedy and built like a racing broom handle.
About 5 years ago we took him to the GP because we were very concerned about his lack of engagement with life on any level. The GP referred him to Child and Adult Mental Health, but DS managed to convince them in a phone interview that there was nothing wrong with him.
I have asked my partner what she sees him doing in 5 years time and she wants him to be living independently. However, she does nothing to enable that: she treats him like a Prince and requires him to do nothing, unlike the girls who always played a part in the running of the house. She buys him rubbish food and allows him to treat the home like a 5 star hotel. She still feels guilty about having to leave him in the care of his grandmother and uncle when she returned to the UK to work and support him. He knows exactly which buttons to press to make her feel awful.
He wants to study computer games design (don't they all?) but to my mind has no prospect of ever getting a job as his communication skills are so dreadful. He has zero life skills and is incredibly lazy. If I make him do something like wash a pot, or a pan, he makes such a mess of it in order to never be asked again. He is OCD about getting dirty and it is painful to watch him do anything.
The situation is making me very depressed and it is beginning to cause friction between me and my partner. He has never been diagnosed with any conditions. What would you advise?