Certainly sounds like the police could be trying a little harder.
According to the Illinois state law, only certain types of fireworks can be purchased and used commercially. Everything else needs a permit. I might want to call the fire marshall to at least have them investigate.
According to a fireworks website, the Illinois State Fire Marshall is responsible for enforcing the fireworks regulations. You may have to escalate to them if the local authorities are no help.
State Fire Marshall
State of Illinois
Division of Fire Prevention
1035 Stevenson Drive
Springfield, IL 62730-4219
217-785-4714
Illinois Fireworks Laws
State of Illinois, Keep Cool Illinois - Fireworks Safety Awareness
As for the underage drinking and drug use, try to speak to the police supervisor and see if the police cannot truly intervene if the mother refuses to allow them into the house or if the officers were just unwilling to get involved. Perhaps ask them for advice on how to handle the situation. I'm sure there are ordinances regarding drug use and underage drinking. Perhaps get social services involved for child endangerment (
Illinois Department of Children and Family Services).
Best of luck