Background info is eldest DS15 has ASD and attends a mainstream school. Does ok academically, really struggles socially (no social life outside school whatsoever despite our best efforts). All he wants to do is video game ( prob very typical of a teen). He never goes out but doesnt seem depressed as he hates social interaction.
Recently I feel like every interaction we have is negative and its exhausting and worrying me. Im nagging and I hate it. He needs micro managing constantly for even the basics of showering / eating / getting up. We have tried everything to promote independence and support any executive functioning issues...bought an Alexa to set all important reminders..he ignores it. Organised his desk to make school work more manageable ...he just doesnt do it. Let him make suggestions on how to be more organised...he doesnt follow them. Arranged an ed psych appointment and explained honesty was vital as we could then support him better... he lied throughout saying hes fine / he needs no support.
Its come to a head today because he is eating EVERYTHING out the pantry even stuff he knows isnt for him. For context he had free access to food / snack basket but we have limited the choice recently as he continued to eat not only his but others and gained a lot of weight (hes now overweight). All siblings are also autistic and some have food difficulties so its important we have the " right stuff" ...we have explained this repeatedly, moved to a higher shelf etc, bought him his own stuff...and yet he still does it. He drank 4 pints of milk in less than 48hours, an entire box of cereal and a loaf of bread. As well as snacks and full meals. We give decent portions of dinner and would love to make them more protein heavy but hes incredibly restricted on what he will eat.
Clearly this isnt a big deal in the grand scheme of things but makes life difficult when his younger sibling becomes hysterical the only food he eats isnt available and I then have to dash to supermarket to replace.
Frankly its starting to make me wonder how much is " typical teen", how much is a result of his executive functioning difficulties and how much is just pure selfishness and laziness.
How do we motivate a teen to consider other people in the house? Is this normal? Maybe we are expecting too much and we should ride it out but I'm worried as he doesnt self regulate he will end up really unhealthy, no GCSES (not because of ability but lack of motivation) and then struggle in adulthood.
Fully aware I'm likely projecting my own issues here too 
. This is a massive rambling rant...sorry ... surely its Gin o clock now?!