There is no point of you trying to prove somthing wrong, when you don't have the knowledge in the subject.
I suggest you use spells, that are already written. Click "Spells" on top.
Casting a spell takes lots of learning. Do you know the moon phases, meditation, etc? You can't just do a spell out of no were. If your brother's don't believe in magic that's their problem. Using energy trying to prove them wrong is wrong. I suggest you tell your brother's to research about witchcraf, wicca, rituals, magic, etc. Give them link to this website so they can explore on their own.