If you read one of the most recent judgements from the ECHR: www.supremecourt.uk/cases/docs/charlie-gard-190617.pdf (And I am going to copy and paste because many don't have time to go read the whole thing)
Para 10
(b) it was not certain whether Charlie is suffering pain but it is likely that he is suffering it and at more than a low level
(c) the clinician in the US who was offering the treatment favoured by the parents conceded that the chances of its securing meaningful brain recovery were vanishingly small (para 105); and
(d) the proposed treatment would not only be futile but might well cause pain, suffering and distress to Charlie.
Para 13: the effect of the judge’s findings was that the harm which he was suffering was “significant”
So he may look peaceful heavily sedated on a vent, but this is likely to be because he is unable to demonstrate a response to pain. The agreement is that he is actively suffering harm.
Para 17 and 18:
We three members of this court find ourselves in a situation which, so far as we can recall, we have never previously experienced. By granting a stay, even of short duration, we would in some sense be complicit in directing a course of action which is contrary to Charlie’s best interests. But, from a legal point of view... are the best interests of Charlie necessarily always paramount? There is, says Mr. Gordon QC on behalf of the parents, another requirement in play, namely that such (human) rights as they have under articles 2 and 8
The conflict between Charlie's best interests and his parents' best interests, and which should be put first were a clear focus of the ECHR's consideration.
Para 15: Every day since 11 April 2017 the stays have obliged the hospital to take a course which, as is now clear beyond doubt or challenge, is not in the best interests of Charlie.
Paragraph 21 also adds something of another perspective, although I won't copy it here. It seems clear that the ECHR had the utmost sympathy and compassion for parents in a terrible situation. However they also mention medics in a situation of having to act unethically and against a child's best interests while courts work out if a child has rights separate to their parents' rights.
In cases where a child is found to be suffering pain and harm, yes they absolutely do.