First, he needs counsel. Second, that counsel can file the appropriate paperwork in the appropriate jurisdiction to modify the numbers.
In no way am I offering you legal advice, and in no way has my comment created an attorney-client relationship. You are not to rely upon my note above in any way, but insted need to sit down with counsel and share all relevant facts before receiving fully-informed legal advice. If you want to be completely sure of your rights, you must sit down with an experienced criminal defense attorney to be fully aware of your rights.
As my colleagues have stated your brother would need to seek counsel in Colorado so long as the court order for child support was issued in Colorado. But unless I'm missing something, how is he paying support if he doesn't have an address to send payment? Child support enforcement is there to make sure that child support is paid, not simply to help mothers so they would be a viable option for your brother. The family support registry is something else entirely and only receives and disburses payments and maintains a record of payments on each case.
This answer should not be construed to create any attorney-client relationship. Such a relationship can be formed only through the mutual execution of an attorney-client agreement. The answer given is based on the extremely limited facts provided and the proper course of action might change significantly with the introduction of other facts. All who read this answer should not rely on the answer to govern their conduct. Please seek the advice of competent counsel after disclosing all facts to that attorney. This answer is intended for Colorado residents only. The answering party is only licensed to practice in the State of Colorado.
The Family Support Registry does not help anyone with child support matters. All it does is receive a payment from one party and disburse it to the other. However, your brother may be able to get the address to which they send the payments from the FSR. He should call and ask.
www.karlgeil.com. This answer is provided as general information about a legal issue, is not legal advice specific to a particular case, and does not create a lawyer-client relationship with the person asking the question.