First, a brief overview of the process:
1. Initial level: doctors will review your son's medical records once he applies for SSI. They will most likely deny your son's claim unless your son's symptoms are extremely severe and it is well documented in his medical records.
2. Reconsideration level: if the initial determination was a denial, you can appeal it. Here, other doctors will review your sons medical records. They will most likely deny again. Depending on your state of residence, you may skip this level.
3. Hearing level: an administrative law judge (ALJ) will review your son's case. You (and maybe your son) will meet with the ALJ and give testimony to support your case. His/her decision is indepent of the prior determinations.
4. Appeals Council: if the ALJ's decision was unfavorable, you can have the AC review your son's case. The AC will decide whether the ALJ did what s/he was supposed to do. If they decide the ALJ made a mistake, they will remand the case back to the ALJ for another hearing. Note that this does not guarentee a favorable result.
5. Court level: If the AC found that the ALJ's decision was correct, you can request the district court to review your case.
Some tips:
- Make sure you do everything SSA asks of you -- complete all the forms, go to all the interviews, give detailed explanations. Also review pertinent impairments here: http://mwww.ba.ssa.gov/disability/professionals/bluebook/.... It tells you what you need to show. Even if you have no evidence of those things, try to show as much of it as you can.
- Make sure your son's doctor documents every pertinent finding. Sometimes, doctors can say that your son has X condition, but do not actually put that in the treatment notes. If the doctor doesn't, there is no way for SSA to know for sure that the doctor actually said that.
- Do everything your son's doctor asks you to do. If he tells your son to do occupational therapy, do it.
- Try not to miss appointments with your doctor or other health professional. This shows in the medical records and SSA will use that against you to say your son's condition is not so bad if your willing to let him miss appointments.
A comment on one of the answers below -- you don't need to have paid into the system to get SSI. For children, it's solely based on whether SSA considers them "disabled" or not.
Hope this was helpful. Good luck!