Mom's advanced directive is misplaced. Do we need a new one?

Normally a copy is as valid as the original as long as: The document states a copy is valid, and The copy is "complete"- i.e. all the pages are attached/ no blank spaces/ etc. Further, in CA, depending on when/ where the advance directive was signed by your mother, it should have either been notarized (Acknowledgement) or notarized and witnessed (if it was signed while your mother was in a care facility- they should have a patient ombudsman who routinely performs this duty).  For more information, you may want to contact the California Medical Association or visit their website - www.cmanet.org  Depending on your situation, you may also want to speak with her primary care doctor to see if they have a copy. Assuming your mother is legally competent (aware and able to understand the nature of the act she is performing/ document she is executing), you may just want to get a new directive. Finally, please keep in mind that the advance Directive is as much for the signer (your mother) as the one(s) designated to make the decisions on her behalf.  To that end, I strongly encourage you to communicate with other family members/ siblings/ etc. who might otherwise expect to have some say in the situation- keeping everyone on the same page generally helps minimize the additional stress of intra-family squabbles during what is already a very stressful time. Best of luck.