In Massachusetts after the death of a custodial parent, can the grandparent take custody or will it go to the biological father?

My daughter has a terminal illness and she will probably die soon. She and my granddaughter's father were not married and my daughter has always taken care of her daughter. She has physical and legal custody. The father never signed the birth certificate. He also has a criminal record. If my daughter dies, will my granddaughter's father have automatic custody of the child, even though he has nothing to do with her, or is there a way I can obtain custody?