Dixied,
Hugs to you, addiction hurts us all, including the innocent children.
I am one of the grandmoms who lost a grand daughter because of my sons addiction. When she was born, my sons GF didn't put bis name on the birth certificate as the father, (smart girl) so therefore, I haven't ANY rights as a grandparent, and have not seen her for 13 years.
(although I'm going to be a grandmom again in March...maybe this one will stick...
)
You do have rights. This is YOUR grandchild. Fight for those rights, if visitation isn't approved.
As for your son visiting, I can understand the EX having trust issues, heck I have them myself with my sons.
Time will heal alot of these problems.
Time and a judge, and your son staying in recovery.
Hugs from one grandmom to another...........