Can I still act as my dad’s Power of Attorney after he died?

No. Once your dad has passed away, any powers you were granted as the agent have terminated. If immediate action needs to be taken, such as paying a funeral bill or accessing a safe deposit box that contains a Will, an heir can petition the court for a special administrator to be appointed. The court will grant the Special Administrator very specific functions rather than the wide range you have as personal representative. On the other hand, if the decedent had a trust, all assets in the trust can be accessed immediately by the successor trustee.