Snorting prescribed medicine

Your Dad is using a "route of administration" that is not prescribed by his doctor. No doctor prescribes medication to be snorted to my knowledge. That means it is at least an "abuse" of his prescribed medication. I recommend you tell your Dad what you saw, unless he has ever been abusive to you. If you are afraid of telling him, tell another person close to you both, your mother perhaps? It is best to face these things head on. I am sorry you had to see that. You don't say how old you are, but I can imagine it is scary, no matter your age. Please let me know if you need any other assistance. God Bless.