While some people call the non-RAD children 'the healthy siblings', that is often far from the truth. 

Even if these children are not suffering the symptoms of these diagnosis they are directly affected most of the time. 

Often the siblings are also the target of the RAD child, and this might be in the form of physical, emotional, or sexual abuse. They can also be the victims of stealing, lying and triangulation. 

It's not uncommon to hear cases of RAD children blaming the siblings for their actions and the parents believing such life for a long time before finding out the truth. 

Also, RAD children usually lie about the parents with other people, but that is not necessarily the rule. We have heard the same heart breaking story over and over about how, after finally managing to make some friends despite the complicated situation at home, the 'healthy' children end up losing their social circle because their RAD sibling started making up allegations and turning everyone against them. 

Another way these children are severely affected is by witnessing the violence displayed against their parents. Usually children unconsciously see their grown-ups ask some kind of invincible entity, which makes them feel safe and protected. Later on as they grow up, they realize that is not necessarily true. However, being directly exposed to that when the child is not emotionally ready to handle an internalized that information in a healthy way can be beyond traumatizing. 

These children know their families are in danger and they feel truly helpless, angry, and scared at the idea of being unable to protect them. 

Another common scenario is them being very aware of all the difficulties the family is going through and deciding to not go to their parents for help or comfort under the impression they will be increasing the already heavy burden if they do. 

'Healthy siblings' learn how to survive, but most of them struggle being able to enjoy living under the situation at home.