As someone with a full diagnosis of Asperger syndrome, married to man also with an ASD, I know how differently people have to communicate with us to get the same response.
As has been said, we need really clear instructions. Why? Because the bit of our brains that normally looks at people, their emotions, their face expressions, their body language etc doesn't work. It's used as a filing cabinet for hobbies instead. No, really. So we have to spend our whole lives rewiring bits of the brain to do the job of the 'people bit'. It's slow and the wiring gets overheated at times, which is why we need the really clear instructions like
"I am feeling really sad - I need you to (whatever)".
We can also be a bit reluctant to respond to unexpected hugs etc because our sensory systems are wired in wrongly so it hurts like hell unless we're ready for it.
It all makes us look uncaring and unfeeling and selfish, but most of the people with an ASD I know are absolutely marvellous individuals once people realise the basics and learn a few new ways to communicate. There are some people who just are not interested in being nice at all, but it's fairly rare. Same as for anyone else in society.
You can imagine how difficult it was at the start of our relationship with both of us not being able to see the others' reactions
And it's true that adult diagnoses are hell to get. I had to go private, at huge cost.
Glad it worked out for you in the end, Thandeka.