There are two parallel issues.
The first issue is that the mother shared an image, that got picked up by the press, she lost control of the situation and her son became a political football. "In a formal complaint to press regulator IPSO, she said she had initially given permission to two newspapers to use her son Jack's image but - after the story was widely reported across other news outlets - she now wanted to prevent any further publication of the picture or his details."
The second issue, and the one more relevant to all of us voters, is the fact that the boy's case happened at all (claims vs reality over NHS support after 9 years of Tory Gov), and in particular Boris Johnson's reaction to questions about it (refusing to look at the photo, taking the journalist's phone and putting it in his pocket, repeating Conservative pledges for the NHS rather than discuss the actual case in front of him). It reminded me of Gordon Brown's "bigoted woman" moment.