First off, no one has said anything about removing anyone's imagination. That is an unfortunate comment probably posted in in anger.
Secondly, Calling the ministry of deliverance an "extremist form of Christianity" is not biblical and may be hurtful for those who may be suffering with a demonic issue. One third of Jesus' ministry was casting out demons and only a fool would ever say Jesus practiced an extremist form of religion.
Thirdly, children can have a demonic issue. The bible records several cases of children being possessed and attacked by demons.
It is very easy to make broad brush assertions that demons do not exist when one has not encountered one. As a boy, I personally encountered a ghost. I still recall this encounter very vividly and I will never forget it. In our society many are just like
Nautilus. His reaction is very normal, very rational and expected for those who have personally seen this junk up close and personal. I respect his opinion and others like it but I know, first hand it is incorrect.
For those who cast aspetions on others in ignorance of the spiritual realm around us, that is harmful, hurtful and insensitive. Many have seen ghosts (demons) and experienced all sorts of stuff like this. As a child I alone experienced this junk and no one believed me, except for my mother who saw my behavior change over a year. Even then, she just knew I was sincere. I learned to not mention this to anyone unless I knew they would believe me.
I agree with Ugly, that we should not derail this post. This mother said she is concerned and we ought to not fight or post negative things back and forth about each other or the views of others when she is hurting and concerned for her child. My advice to her would in no way harm her child if I am wrong and this is simple imagination. On the other hand, it might help her and her son if I am right. So let's all stay on point and not seem like a roving pack of rabid gerbils and see if we can support the OP.