My bearded dragon died?

Ok i dont know what happened on this morning i was looking at him with his eyes opened and all dried . i dont understand i fed him my mom fed him with plenty of water . i have a heating lamp for him he was a good boy and he is 4 years old and he died august 25 which is today . i love him so much , i her lots of people ha this with their beardies is it going around? what do i do when he dies do i bury him? my mom wants me to trow him away cus she hates reptiles and dont want to see him dead. what do i do