Unless there is a provision in your mother's power of attorney that either appoints the surviving spouse to act as one of your mother's attorneys-in-fact or gives you the authority to name the surviving spouse to act with you as one of your mother's attorneys-in-fact, your mother will have execute a new power of attorney to appoint the surviving spouse as one of her agents or attorneys-in-fact. Powers of attorney, though, are governed by state law. So while I believe the above would be true in most states, it would be advisable to review the POA with an attorney in your mother's state of residence to see what effect your sister's death had on the POA and what steps, if any, can be taken to have her spouse appointed to act as a co-agent with you.
Answered on Aug 30th, 2013 at 2:49 PM