I second this. I found it extremely difficult to finish my PhD 12 years ago. It wasn't because the subject was difficult or complicated but because I came directly from a Bachelor's degree into a UK MPhil/PhD programme. I remember at the beginning being sited in front of my desk asking myself: What do I do now? And every time I had a meeting with my supervisors and I asks them whether what I was doing was right/wrong, their answer was "that is great, you are doing great".
Nevertheless, I had great supervisors: After about a year of work, we decided that my work was more oriented towards what my secondary supervisor was doing, so my main supervisor took a step back and let us do our work; he still watched closely although more about "form" rather than substance. In retrospective it was an amazing experience.
Now, with regards to the (now deleted) article. I blame the supervisors but from another point of view: They should have used their network to contact people that knew about Quantum Computing. They all (including the PhD student) already had the most difficult thing: The grant. They just needed to use it.
If I were the PhD candidate, I would have looked for who were the main Quantum Computing researchers, and ask my supervisors to contact me with them. If they didn't want to, then I would contact them directly and start having an "informal" mentorship with them. Professors salivate at the prospect of having a "free" PhD student working on some of their projects, so I'm sure he would have been welcomed by some of them.
I feel that the main problem with the student was his inexperience, and his supervisor's inability to support him.