public OnPlayerPickUpPickup(playerid, pickupid)
{
        for(new i = 0; i < MAX_PLAYERS; i++)
        {
                if(pickupid == tombstonePickups[i] && i != playerid)
                {
                new tombstring[MAX_PLAYER_NAME+20];
                GetPlayerName(i,tombstring,MAX_PLAYER_NAME);
                strins(tombstring, "~g~+$400 ~n~~r~Coffin of:~n~~w~", 0);
                GameTextForPlayer(playerid,tombstring,3000,3);
                DestroyPickup(tombstonePickups[i]); //Since you want to remove the coffin of the player that is dead, you'll have to place 'i' and not 'playerid'
                tombstonePickups[i] = -1; // Same for here
                GivePlayerMoney(playerid, 400);
                break;
                }
        }
        return 1;
}