She absolutely could face jail time, but will get a lesser sentence if she admits to a problem and goes to rehab.
I was in rehab with a girl who was doing the exact same thing and she had her kids taken away and after she completed rehab she had to report back to jail. A squad car came and picked her up. She wasn't even able to have weekend passes like the rest of us, and she could live in off campus housing after detox.
Not only was she 'doctor shopping', but she was calling in her own scripts.
Your friend better get help and soon!
Penny