My brother is a drug addict, and I don't want to bury him in my grave?

One must denounce those who commit forbidden acts according to one's ability. If the person is discreet about them, then one should denounce them privately and conceal their fault. If they are open about them, then one must denounce them publicly. It is recommended to boycott them, both in life and after death, by not attending their funeral procession or offering prayers for them. They should be buried in public Muslim cemeteries, not private ones, if they were open about their forbidden acts. Two people should not be buried in one grave unless absolutely necessary. The burial of two people in one grave does not affect the transmission of punishment or reward between them, for "every soul, for what it has earned, is held in pledge."