Big brother?

Very difficult to understand what's going on in this case of the parents who took their child from a hospital here in the UK and went with him to Spain to try to get treatment for him which was unavailable under the NHS.  It seems to be generally agreed that, whatever the wisdom of what they did, they broke no law by taking him from the hospital, nor by taking him out of the country and yet somehow a European arrest warrant was issued, and indeed the parents have now been arrested and are it seems in custody - in handcuffs, no less!.  This really calls into question the right of the state to override parental decisions.  It seems that the hospital were considering trying to get an order which would have banned the parents from entering the hospital to see their son - all because they were in disagreement about his treatment.  And whether they were right or wrong, that strikes me as a shocking thing to do - or even contemplate doing.  It may be there are things we are not being told, but on the face of it, this is a deeply disturbing business.