I'm an academic. Just tell him it is completely normal and expected that students go to their tutors to ask questions. We don't think those students are stupid. It's the ones who don't use the resources provided to them (academic office hours being one of them) to sort out problems that I am most frustrated by.
The peers that he is comparing himself to will be emailing/visiting tutors and asking for clarification and guidance. It is often the more engaged and ambitious students that get in touch with me.
There will also be study skills resource at the university, separate from his tutors. e.g. a 'centre for academic skills' or similar. That can help with more general issues around academic study. Subject specific issues are better directed to tutors though.
If it helps him to feel better about this, he should take some time to think about what he is finding hard, and organise his thoughts into a few key questions, so he can present himself as a sensible, proactive student, rather than just a rambling mess. Although, to be clear, I've dealt with many rambling messes in my time and have felt nothing but empathy for them.
I would say that I would be quite judgemental of an undergraduate student who had a private tutor. Partly because there are risks about academic integrity if they are involved with any assessments, but mainly because universities provide all the support and resources a student needs and it seems like an indication that the student is unwilling to be proactive about their studies and is resisting their development into an independent learner.
Your son is paying £££££ a year to do this course, and to be unwilling to take the opportunities provided to them via the university (whether wellbeing or academic support) is concerning and non-sensical. Literally no one will have any opinion about him accessing university services.