If my daughter has Autism and Intellectual delayed, should I mark her has disabled?

[Paganoughtous]

Yes, you definitely can.  If you haven't already, look into whether or not she qualifies for state medicade/supplemental insurance to help cover any and all copays on medical visits, exams, diagnostics, prescriptions...  My heart goes out to you. 

[LeonardS]

Yes, if your daughter cannot engage in any substantial gainful activity because of a physical or mental condition and a  doctor determines the condition has lasted or can be expected to last continuously for at least a year or can lead to death she would be considered disabled for tax purposes.  Ref: IRS Publication 3966 (Rev. 5-2021)