I genuinely do not care how true it is whether he is autistic or not, but let's say he is correct about it, I did read about an interview where he briefly talked about his problems with social life which he attributed to autism, and many have observed him having difficulty with eye contact in interviews.
Most notably though, Elon Musk is obsessed with certain words and patterns, especially with the letter X. He initially wanted to call PayPal "X.com", he calls his own tech company SpaceX and the only reason he named Tesla into Tesla was because of his obsession with Nicolas Tesla and science fiction, which also inspired him to startup SpaceX. He obviously rebranded Twitter into X, another example of his obsession with the letter X. It is therefore not too far off to say that Elon Musk could have science fiction and the letter X as some of his special interests, since being obsessive about these things are traits more associated with autism. A lot of his decisions in this area do not seem to be beneficial to him in business because of the inability for these decisions to conform to normative and expected social standards e.g. rebranding Twitter into X, which could also point to autism since autistic people when being just themselves, may do unconventional things that would not be received well by the general public but feels good to the autist.
A weaker argument to the point is that his daughter his transgender, and while it is not well understood yet, gender nonconformity and transgender experiences have a very high comorbidity with autism and since autism runs in families, there's nothing that says transgender experiences could also run in these families. Also, let's be real, but the way he named his children in his second and third relationship are ludicrous and while it's not unheard of that very rich people name their children the most eccentric things, I do think Elon Musk scores quite highly on that list. Especially since most of the names seem to be related to some of Musk's personal interest in say, science fiction and comics.
With that said, who cares if he's autistic or not? Not like it's going to change the way he's just an as*hole.