Should I get tough and destroy all my brother's voodoo and satanic items or would he get revenge on me for it?

For more than three years now my 13 year old brother has been practicing in some sort of dark arts and he won't tell us exactly what it is but we see the evidence everywhere. He takes vials of his own blood with a syringes, he makes hollowed out dolls filled with skin, hair, nails and blood from other people, he writes in the "cursed language of demons" as he puts it. We had to move his room into the pool house to get the voodoo out of the house. I am watching him and my sister by myself right now and he has already tried to kill her birds, ruined her favorite doll, ruined many of her books and burnt down her playhouse. I am thinking of just taking a tough approach and taking all his voodoo items and putting them in a metal barrel and burning them all down. Should I do this or would it anger him to violence?