My son has legal sole custody of his son and the mother is in prison for child abuse. My son hasn't ever taken care of his son, he has been in my care since we got him from social services. How can I get permanent custody of my grandson?

No my son is willing to give up rights. And also when the mother gets out will she get the baby back if I get custody? Or can she take me to court and get my grandson? Als does the mother have to sign her rights over too or is she not in the picture?

Apply to the court for guardianship. With respect to "custody", parents are preferred over grandparents. So you would ask for guardianship instead. Is your son likely to fight you on this?

No my son is willing to give up rights. And also when the mother gets out will she get the baby back if I get custody? Or can she take me to court and get my grandson? Als does the mother have to sign her rights over too or is she not in the picture?

SO... where do you get a title to a kid to sign over anyway? Family Courts are who take away rights and assign custody...

And the moms rights to her child will supercede your own as a grandparent. However the courts will view her suitability to raise the child... her chances of getting the child back are very much in her favor... but not guaranteed.

The father has legal sole custody of the baby now. But I hve had the baby in my care for over a year.