You have received some very good advice here but I will just add that a friend of mine works as a nurse in a private doctor’s office. She has shared with me that it is becoming very common for parents to come into the office complaining that their child has sleep issues. The doctor always starts with limiting “screen time.” This includes video games, laptops and phones. Apparently its become a huge problem among our youth because they are spending so much time on a screen, often close to their face (unlike television time), and they are finding that the brain doesn’t get adequate time to shut down and relax before trying to fall asleep. The screen acts as a constant stimulant. This might be a place to start for your daughter to work on her sleep issues rather than smoking pot. The doctor suggests stopping all screen time at least an hour and half before the desired sleep time.
With all due respect, I find it concerning that you don’t want to ask your daughter to see her grades until in the therapist office. This suggests to me that your daughter is the one in control rather than the parents. You are the parent who is paying some, if not all your daughter’s bills and should be seeing the grades the day they come. Until she lives on her own and supports herself, you are the parents and what you say goes and her grades are certainly your immediate business.