Daiper change, without there irritation and illness.
No food. There is illness, malnutrition, starvation, death.
No healthcare? Needless suffering. Needless illness. Needless death.
No religion? No problem.
No baptism? No problem.
No car rides? No problem
No grounding? No problem
No sex ed? No problem
No vaccines? No problem
No braces? Most the time no problem
No dietary restrictions such as vegertiasm or veganism? No problem
No daily bath? No problem
No daily teeth brushing? No problem
Parents make choices for children. This is okay. Restricting choices to what refraining from constitutes the low level bar of negligence is silly.
Legal standards of harm are a good place to draw the line. If your actions are unreasonably harmful, then you shouldn't do it. We assume that parents have the children's best interests in mind. For this reason parents can consent for a child.
Parents choosing to baptise their infants...not harmful.
However if it was the parents instead of the big brother/sister i am not sure the child should be denied remedy. However, i can accept that such a remedy would have a higher burden to overcome, specifically the presumption that the parents were acting in the child's best interests.