Client lives in California, but was born in Macau (think Hong Kong). Client needs to have his Macau birth certificate certified for some reason. To do this, Macau needs his mom to sign off on the certification.
Client's mom is in her 90s and is in frail health so client does not want her to travel to Macau to just sign one form. Client can get his mom to sign the form in California and then get the form notarized, but is not sure if this has any meaning for documents used internationally.
I am a China lawyer and here is my understanding according to official information available.
First question we are to ask: Is this for the purpose of using in the US? If it's immigration related, for example, they need to get the proper document issued by the relevant authority in that country. You can find country specific information here, and learn whether and how such a document can be obtained:
Scroll past the visa issuance fees and down to the relevant document.
http://travel.state.gov/visa/fees/fees_3272.html
First, though, the key is finding out for what purpose is this document being used? US purpose? Macau purpose? Other? and what purpose exactly? US immigration? Travel? Financial? Etc..
If it's a US document, here is additional info to peruse on authentication and apostilles (and Hague Convention members) ...
Authentication and Apostilles:
http://travel.state.gov/law/judicial/judicial_701.html
Also, here is general judicial assistance info by country.
http://travel.state.gov/law/judicial/judicial_2510.html#M