1. If you want the effect of the medicine, you should prepare the medicine as directed. That said, the seed by itself will also have some benefit.
2. That is up to you. The effect of the medicine depends on the severity of the illness, the quality of the medicine, the behavior of the patient, and the karma.
3. Seeds can be stored.
"Do not worry; cultivate the habit of being happy." - Samael Aun Weor