I'm the biological father of a baby whos' mother passed away now there is another man's name on the birth certificic but he has agreed to sign his rights over to me and put my name on the certificic... Nows the tricky part... The baby's mothers mother has filed for custody of the baby and will not let me or my parents see the baby and has verbaly threatened that she will run away if we try to come see the baby... I want custody but so does she whut should I do?

The only thing you can do.. go to court.

Yes, the only thing you can do, file for custody, ask for a DNA test to prove you are the father, show that the wrong person was listed on the birth certificate,