Gosh, where do I start? This is not definitive. It is not placing all individuals with autism in one bag. As Temple Grandin says 'You meet one person with autism, you've met one person with autism'. It is so highly individual, that what people generally associate with autism, may not always be apparent, especially in older people.
Let's start with empathy. It isn't true that those with autism lack empathy, often it's quite the opposite, especially when there is an attachment to someone they consider special. It is true that those with autism are ultimately anxious. And have difficulties in reading social cues both verbal and physical. There can be difficulties in processing information which has emotional content.
When someone is highly anxious but doesn't know how to successfully read verbal and physical cues and hasn't learned how to offer suitable support to another who is struggling, this can ramp up the anxiety, which in turn can lead to a sensory overload, that triggers a number of responses in that person, several of the most common are to switch off and/or walk away or conversely to explode/rage.
My personal opinion is that there are a lot of undiagnosed/unrecognised adults with autism out there. When you consider that autism as a diagnosis was only really recognised in the 70s (and it tended to be the more classic behaviours associated with autism that were recognised), that leaves a population of people born in the 40s,50s,60s,70s rattling around, often in relationships that have caused their partners to doubt their very sanity because they are faced with a plethora of confusing and conflicting behaviours. Many people with unrecognised autism have evolved highly sophisticated ways of managing what is essentially a life of tension and ultimately stress. One of the ways of managing that stress is to pursue solitary hobbies - running, fishing, diving - for example, without necessarily realising the underlying reason.
So, to answer your question, what was it about your post that threw up red flags?
- his inability to manage his emotional responses (does he even recognise his emotional states)
- projecting an emotional state (which he may not recognise in himself) onto another, in this case, your son
-not being able to handle anything being wrong with you (anxiety because he has attached himself to you)
- needing to have what he wants, when he wants it (eating early)
-having rules that make sense only to him (won't cook for you, because his rule in his head is that you cook. Makes no difference that you've been at work all day.)
-not being able to read social cues (hanging around when you're with your friend)
-being critical of measurable skills like driving
-assuming that he is correct and others are wrong, even in the face of incontrovertible evidence (the way you have raised your son)
- taking on projects that will garner external praise from you and others ( doing up the house/garden) but not interested in the background, invisible drudge work around running a household
- either very 'good' with money (often controlling), or appallingly bad (doesn't surprise me that he is an accountant)
You haven't mentioned specifically these points but these would also be pointers for me:
-not able to take on board a general principle - will try to bring things back to a very specific point in an argument/discussion and be unable to get past a specific aspect in a discussion with you
- promise change but can't keep it up over a sustained period of time
-doesn't learn from mistakes, so life can feel like Groundhog Day for the partner
-likes things to be clear cut/black and white
-oftens partners up with someone who is emotionally savvy and willing/able to do all the hard work (i.e. emotional stuff) in a relationship. That person becoming worn out/ground down over time.
Having said all of this, this is perhaps an explanation, but not an excuse for the way in which he has behaved.
I don't know if this helps Poppy or whether it muddies the water for you. I do hope that you are able to keep on gaining strength for yourself.