It depends on a couple of things. Firstly how knowledgable and confident is your DS about the uni options available. Given their ability level and subject interests, are they properly aware of the different courses available and wanting to look at good or best options available for them?
Secondly, as a parent, how confident are you about all this? If you know their subject and about the unis and have discussed it and feel your DC has shortlisted good places, then you could feel confident to let them look and decide. But if you yourself don’t know much, you might feel that it would be helpful all round to go too. You will want to know your DS has made a good choice given the future implications and cost of it all.
Families vary. Some teens are extremely capable and independent. Many are less so. It is a big decision and so one not to be taken lightly. Many would feel a second pair of eyes and a bit of discussion after an open day could be useful. Some teens are up for discussing with parents and see that as useful. Others don’t think parents have anything to add or can be immature about just wanting a day out with mates. Some don’t engage with the topic of courses and places as they should given the cost implications on themselves.
I think you have to know yourself and your own level of knowledge and confidence about the process and also to know your own child’s ability to make this big decision.
Some families will have done lots of chatting about courses and unis for several years. A shortlist has already been drawn up which is sensible and further discussions will be held after the visits have happened. The child will be open to hear thoughts of parents and consider them. The parent will be open to the child making final decision, knowing all of the possibilities are decent.
But other parents have no idea. The teen also has no idea. No-one engages properly at all. This is where kids end up on the crap courses the government wants to shut down - they dont realise they are crap courses.
Knowledge is power. The teens need knowledge to make good decisions. Some can generate. All that knowledge totally by themselves. Most would benefit from a level of parental input. This can vary.
As others say, most young adults might have a parent look at a property they’d like to buy or maybe a car. They might not go with what their parent thinks in the end, but they’d ask for input from their parents and not their friends. This could be seen as similar.