Question about Social Security Disability Benefits?

I too have a son on disability ( Down Syndrome ) and from my understanding they can lower the amount he receives depending on the amount of earned income she gets. If you make over $1800 a month then the amount of the disability check goes down, it doesn't stop it just goes down a few dollars a month. That's how it is in MO I don't know if it's different in different states. You may be able to find out from the Social Security office if he is still on disability by just going in and showing your I.D. I don't know if you have to be the rep payee on his checks, if so, have the judge put in an order to have her provide the doents proving that your son no longer receives checks.