I am sympathetic and really understand your concerns. Did you parents board, and did your son have a good time? In my case, some of the best years of my life were boarding in senior school. That was before the arrival of the snowflake generation, and the spread of the gaming discord culture of course.
For me as a former boarder I always approach a school with the assumption that pastoral care at any school is window dressing at best. It is the community in your dorm (and to some extent in your year group) that really counts, and how they deal with things amongst others. Adults can try their very best to control teenagers, but we have all been there… teens are teens behind closed doors, and boarders are no different.
My positive personal experience aside, I also feel that boarding in this day and age is at a premium. In a world where gaming and discord chats monopolise time away from socialising and friendships (and are used by many as a way to escape) where else, how else could you build lasting friendships for life? Where else, how else can you learn to read the room, earn trust, learn to be respected, build loyalty, understand how others in your generation really think, find your way out of seemingly impossible situations, or build rock solid friendships for life?
It is unlikely that the time eater Fortnite or the dementor Discord will prepare anyone for life in the real world with other human beings.
When it comes to a school, I am placing my bets on selection and culture, which can be best observed by watching the boys interact with each other (and with the outside world), especially when noone is looking. We observed a sense of loneliness at Eton (single rooms? shared dining?), a sense of exclusion at Marlborough and Sevenoaks (posh is everything), and a sense of too busy to think at Harrow (every minute is packed) kicking the can down the road. We found the culture of Winchester appealing, as boys in general seemed to be good humoured and gentle. It is also very familiar in the sense that the adults are adults and respected.
In the corporate world, there is a saying that culture eats strategy for breakfast. In due diligence, the future fortunes of a company can often be very accurately predicted by just observing the corporate culture, as it defines everything. Investment banks place more emphasis in this than on certain financial ratios, for a good reason. Words, actions, instructions and even reprimands are read and understood in that context: executed without questioning, interpreted thoughtfully and occasionally argued, taken to heart, or even laughed at or resisted, etc.
In case of a boarding school, I would argue that culture and selection (of the right pupils) eats pastoral care for breakfast. The intervention of any adult will be read in that context, just like in the corporate world. Best case is if there is minimal need for pastoral care.
I also understood that pastoral care at Wincoll is embedded into daily life, e.g. Div dons are always on a lookout for potential
issues. Did your son have a similar experience?