I'd suggest seeing if something is happening that is making him more stressed in recent times. It could be his job or if he's not working, that could be getting him down. Unfortunately, having AS doesn't stop people from acting like jerks and at some stage, he has really got to sit down and look at himself and how he's acting towards you and work out a way to stop being so mean.
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Break out you Western girls,
Someday soon you're gonna rule the world.
Break out you Western girls,
Hold your heads up high.
"Western Girls" - Dragon