And my autistic child had a 1:1 aide when he was younger.
It 100% depends on whether or not a 1:1 aide is needed to allow the child to access their education. The child's diagnosis or classification does not matter
Our district has had 1:1 aides for....
Children with behaviors that need constant redirection or multiple breaks from the classroom throughout the day.
Children with complex medical issues that may need immediate, life-saving treatment at a moment's notice.
Children with physical disabilities that need direct assistance constantly.
Children with major communication issues that need a 1:1 aide to facilitate (a sign-language interpreter, a communication board helper, etc)
When my son was in 1st grade, the IEP team decided that he needed a 1:1 aide and the sped director tried to say that she'd forward the "request" to the superintendent. I explained to her that the superintendent was not a member of my child's IEP team and therefore had NO say in whether or not my child got the 1:1 aide that his IEP team deemed necessary. She backed down immediately and the 1:1 started the following week.
The IEP team is the only group that has the legal authority to decide whether or not a child needs ANY specialized educational service including 1:1 aide, placement in a private school, extra time for testing, etc. In order to overrule an IEP team, one must go to Due Process.