I think creating some space and working with a police station outside of your town is the safest POA. Gather as much information as you can. Do you know where you were born (hospital) or where your birth certificate is? Get information on who your dad is and anything you can gather surrounding his death. Maybe reach out to his family (if he has any) to get information and possibly find some refuge with them. Do you have samples of the pills your grandma has been taking to have them checked? Definitely make copies of the diary and don’t give the original to anyone. Write and record everything you possibly can. Keep us updated.