Children using drugs

3 yrs ago a judge granted joint custody. I had full custody with our 3 children now 11,13,and 14. Since children have been in the primary custody of their father they have needed medical and mental attention. DSS has been called on more than 4 occassions and currently has 3 open investigations. The last of which my two oldest boys were found with drugs in their system. The childrens’ father drives trucks long distanceand hardly ever home. Since our divorce in 2002 has been married, moved and different schools 3 times. With one charge of bigamy. I am a single parent without an employer and staying at home with parents trying to go back to school in the spring to finish AAS degree. Cannot afford attorney but know that the children need me more than ever. PLEASE HELP!!! What are my options as the non-custodial parent?