Does my son qualify as being disabled for filing taxes and claiming him as my dependants because he was diagnosed with having asd (Autism)?

You have not told us how old your son is.   There is no credit or tax advantage on a federal tax return for saying a child under the age of 12 is disabled.   If you still need to pay someone to take care of your son while you work, you can still get the childcare credit even if he is older than 12.    If he is older than 19 you may still be able to claim him as a qualifying child even if he is not a full-time student.

Provide some details so we can be more helpful.

And....state laws vary, so you might find that there is a state credit that helps you out.

For purposes of whether you can claim your child as a dependent, "disabled" means "permanently and totally disabled." Here's the definition of permanently and totally disabled from IRS Publication 501.

Permanently and totally disabled. Your child is permanently and totally disabled if both of the following apply.

• He or she can't engage in any substantial gainful activity because of a physical or mental condition.
• A doctor determines the condition has lasted or can be expected to last continuously for at least a year or can lead to death.

But again, this would only apply to someone who is 19 years old or older. If he is under 19 it doesn't matter whether he is disabled or not.