Thank you for your question and welcome to Health Central's ADHD Community.
It would be impossible for me to say whether or not your child can receive SSDI benefits. This is a rigorous process and depends on the extent of a child's disability. Simply having ADHD does not qualify a person for SSDI, it would be based on the severity of symptoms and how those symptoms impact your child's life.
According to the Social Security Administration (SSA), the definition of a disability is:
The child must have a physical or mental condition(s) that very seriously limits his or her activities; and The condition(s) must have lasted, or be expected to last, at least 1 year or result in death.
If you believe your child fits this description and you want to know more, I would suggest contacting your local social security office and requesting the forms to file for SSDI.
You can read more at:
Children with ADHD and SSDI Benefits
I hope this helps.