- His disability must have begun before age 22 and be severe enough to keep him from doing substantial work,
- He must be unmarried, and
- He must not be eligible for a higher benefit based on his own work history.
The benefit rate for a disabled adult "child" while the parent is living is generally 1/2 of the parent's full (unreduced) Social Security benefit. If the parent dies, the disabled child's rate is increased to 75% of the parent's full benefit. And he can continue to receive these benefits regardless of his age as long as he meets the basic requirements listed above.
The Social Security Administration also administers another disability program called Supplemental Security Income (SSI). Even if both parents are still working, your son may qualify for SSI now if he has limited income and financial assets. In most states, people who receive SSI payments automatically qualify for Medicaid. Check with Social Security for more information and to find out how to apply.