Adult son with undiagnosed High functioning Autism or Aspergers meltdowns

Hi Everyone, I am a mother of an adult son in his 20's who still lives with me.  This is my first time, coming onto a support group regarding my son.  

He has an amazing job, did well at University and refuses to get diagnosed, as believes there is not the right type of help out there from anyone that understands.

I feel guilty as a parent for not pushing for a diagnosis when he was a child.  His autism didnt even enter my mind until he was a teenager, now looking back at how he was as a child it was so obvious, I feel terrible, even so I spent years, trying to help him.  Infact, I really felt all was ok and as a family we were doing ok.

Until I became ill nearly 3 years ago, in and out of hospital, diagnosed wirh 4 chronic illnesses and ended up in a wheelchair.  I am now walking again and rebuilding myself and my life.  My son did not acknowledge my illnesses, despite being in and out of hospital etc, he said I was lazy.  Now I am more mobile, he says I have bi polar (as no longer lazy) and refuses to speak to me, we havent had a discussion since the day my health deteriated, he estranged himself from me, but still lives in my house.  I moved a bin out of my way and he had a huge meltdown, a few days ago.

This is why I am here, I accept I have lost him.  But I love him and have told him that I will always be here for him.

Is this type of behaviour typical?  Can anyone give me any advice regarding how to reach him?  I am at a loss.

Thank you for reading this.