my son and daughter in law have a heroin addiction they have a 3 year old son

They moved in with us after she lost her 5 week job because they got into a car accident for the 4th time I. Less than 6 months. They said they were clean but my son was in accident 5 days ago and they confessed to still doing it. I brought her to the doctor with the understanding that if they want to live with us I would hold their meds and give them as needed. On way home from the cvs she grabbed them out of my hand and I pulled over she grabbed her son got out and sat on the side of the road. I went back with my son. After calling police. We found them she was disorientated. She said she threw the bottle in the woods. It with in 30 minutes she was totally incoherent, smoking an imaginary cig laying on my floor.. he took her to bed even after I told him she could die or go into a coma. Today she freaked again only this time said her sister was going to send her plane tickets to leave the state! She has not taken care of him all summer! Help!!!