Although accidents do happens, keeping family together when one member has to travel a lot is very important. Care should be taken but mistakes and accidents also happen in families homes and it is understandable when you have a lot of people living together or traveling together that bad things may happen. That is life.
Regarding the Cyrus Bus Fire the young siblings of the stars should accompany them on tour if it is not interfering with their social and educational upbringing. If it begins to be an issue I think that the parents need to decide if this is the best possible thing for these children.
The young siblings of any touring group are better off to remain at home. Though touring with a group is educational in some respects, it deprives children of schooling, neighborhood friendships, and all the other ordinary experiences of growing up. Touring also exposes young siblings to dangers that would not be present if they remained at home, such as vehicular accidents.
While it is nice for families to stay together, younger siblings should not be on tour with their older siblings. There are lots of sex and drugs on most music tours and children should not be exposed to them. There are also many late nights and lots of travel which will mess up their routines.