Child custody

My boyfriend has a child who is 2 years old. He is staying with his grandmother right now until my boyfriend gets off house arrest and can take full custody of him. My boyfriend & his baby’s mom do not have a relationship anymore because she is not a good mom. She has a history of drug use and other unresponsible things. My boyfriend got out of jail in Dec 07 & has shown up to court for drug test & passed every time. The mother on the other hand has not shown up for ANY drug test! The court has awarded the grandmother guardian custody until my boyfriend can get off & provide for his son completely. & the mother can NOT be alone with the child more than 3 hours. This past month or so… we have a feeling she is now living at home with her mother & the child. This worries us because we know of her past & don’t want him around that. Today my boyfriend called the case worker who worked on the last custody & found out that the mother is trying to take full custody of the child! Is this possible??? The grandmother has known from day 1 that my boyfriend has plans to buy a home & take his son full custody as soon as he gets off. To find out they are going behind his back to try to get the mother full custody is ridiculous! Is there anything I can do? We can do? Doesn’t she have to prove that she is clean & can take on the responsiblity of the child. She doesn’t even have a job & I am sure she doesn’t have money saved up either! I am extremely worried for the child! I love him to death & have completely accepted him as my own! My boyfriend has 3 months left of house arrest, works a full time job, makes great money, has money saved up for a home, still can pass drug test! Please someone help!!!