Congratulations to your child. What an exciting time ahead.
My impression from my choir child is that being a choral scholar is great - it gives structure to the week and rather than tempting you to socialise only with the choir, it tends to give you more than one set of friends - choir friends, and college/other friends. However, in the beginning especially, it is very nice to have the choir as a secure group.
How much time commitment does your scholar have ?
For organisation I think it depends how much choir is being expected - for the 6 service a week choirs the pressure is considerable. For those doing three or four services a week it is far more manageable. My impression is that it does add a degree of pressure and it is important to be careful with your diary as a lot of planning is done months ahead and double booking is greatly frowned on.
However I would say that the rewards make it well worth it.
Services are a good time for contemplation, and give you a moment apart from the rush of college life. Also singing at such a high standard is rewarding in itself. And there are often other benefits - tours to exciting places, and the odd free meal don't go amiss.
My biggest tip would be to use a diary. And your phone calendar. And reminders.
Also, if they are a cassock wearing choir that has a sensible shoe requirement, buy a pair of choir regulation satisfying shoes that get stored in the chapel. Then running in from sport in trainers doesn't matter ! The cassock covers up the sports kit and only the very proper shoes show at the bottom.
My other tip, for the parents, would be to go to services if you can. Being a choral scholar is hard work and it is nice if people come to hear you. Unless DC are singing in one of the more famous choirs they are likely to be often singing to very small congregations. (Obviously if it is Magdalen, Kings, Trinity etc that is nor really a problem !)
I am sure there are better tips out there !