From the description, it sounds like the team has started excluding him based on similar communication gaps as the manager is seeing.

That’s a material deficiency, that even an autistic employee is expected to fix.

It’s hard; no doubt. But if you had a person for whom coding didn’t come naturally, they would still be expected to fix it even if working on the issue is harder for them than for someone else. Similarly, even though soft skills are harder for autistic people than for others, there is still a minimum standard you must meet.

Alienating your entire team would count as falling below a minimum standard on teams I’ve worked on, especially if they were being avoided for work as in the OP’s example.