The disability question never showed when doing my sons taxes and he has a disability and his taxes have already been filed. Can I fix this?

[xmasbaby0]

You might not have to.   You have not mentioned how old he is.  Claiming that a child is disabled does not yield any federal deductions or credits---unless he is over 12 and you had to pay someone to take care of him while you work.  Or if he is a disabled adult who has some income but is still being claimed as your dependent.   Provide some details.   Or do you mean you filed his tax return did not enter his disability INCOME?  

[gailspad-hotmail]

My son lives with us and suffers from OCD and anxiety. Both  somewhat severe. He is an adult.

[xmasbaby0]

Did you claim him as a dependent?  There is nothing to put on his federal tax return about an anxiety disorder that would get him any sort of deduction or credit.   The only disability to be claimed on a federal tax return is blindness--which gets you a higher standard deduction.