I have a personal experience with someone who sounds similar to your son. Sadly I was married to him for 33 years before I finally walked out. Back in 1974 when I met him in college there was no diagnosis for ASD or Aduld ADD.
I saw red flags before the wedding which was big. He always bragged about how smart he was, his high IQ & how well he did in high school but he barely passed his Computer Science major for his BS degree. The excuse he gave was that he was working & didn't waste time doing work or studying in classes where he "knew" he was smarter than the professor. So getting hired with a low GPA outta college was tough & the company he wanted hired by wouldn't hire him. He was mad at them because as he said, my GPA doesn't reflect how capable I am. I was mad at him & let him know tgat his crappy GPA was a direct reflection of his crappy attitude. Those 33 years all reflected that same bad attitude until I could take him destroying my own life no longer. At age 54 we were in therapy together & an attitude topic came up & I dumped everything in that session & our T basically said my H (at that time) had the emotional maturity of a 13 year old.
I left soon after that when I sold the family house I inherited & had the $ to leave. That was 16 years ago & using his emotional immaturity & his diagnosed adult ADD & tge other symptoms of ASD that seemed to my T's where I moved to, to be very much possible. He lost everything I walked away from because of the fight he was giving me about getting divorced. Come to find out, he was sure that a divorce would make him look like a failure....but losing everything he owned wouldn't? His mind does not function normally & until I realized why, I EXPECTED him to act like a normal intelligent person he claimed to be. He never learned the hard way. He is still living on overdraft coverage & credit he only pays minimum on & has made some major STUPID decisions that I have had to hire lawyers to resolve even after the divorce is final. Lots more to this.....but the point is, no matter how smart they are or how lazy they look to us, there may very well be some underlying mental condition that is causing their brain to short circut from how we expect. Worth it to have a knowledgable professional assess at this point so he & you can have actual realistic expectations or know for sure it isn't because of those reasons.