DPOA and Signing ?

Sorry…i apologize but maybe this should have all been under one thread.

QUESTION: Can the DPOA be signed while a patient is in a Nursing home or ALF?

Its probably best if my mother gets it before….but her health has deteriorated…and she probably needs full time or part time attention (help with shopping, drs visits,etc).

In what instance would a DPOA not be recognized or counted as not valid?

thanks very much!