How can i be at peace with my uncle?

Sorry your uncle died. The best way you could respect him and remember him is to yourself stay off drugs and smoking . Smoking kills just as many people. You really must miss him a lot, because you think of him a lot. That is ok. Time will heal the pain of loss and then you can remember fond moments with your uncle. Maybe in time your cousins may come around and want to talk to you also. Remember, they are hurting too and lost their dad.