Do we have to let her see her and talk to her and where do we stand with this?

My husband recieved full custody of his daughter when she was 3 months old. The mother has never had any kind of custody since her birth. The mother had a child previously and he was adopted by grandmother due to moms use of drugs and neglect. She was on drugs when daughter was born and has actually been charged with a felony but served no jail time, and is now to go to court over felony theft next month. She is allowed supervised visits at my husbands discretion, but until she turned 3 she never even asked to see her (to our knowledge), which we allowed since it was her birthday and she made a huge scene at our home. (June 2011) Her maternal grandparent was given grandparents visitation every friday night, which is encouraged because she is able to see her brother. Now she is insisiting my husband allow her to see her because she is off drugs and is now being given unsupervised visits once a week for 2hr periods by DCFS with her 14 month old baby. My husband does not trust this woman, for good reason, especially with his daughter. What if the grandparents let her see/talk to her without our knowledge?