I empathise so much with you, my daughter sounds very similar to your son, obsessed with every essay being her best work. Re-writing and procrastinating.
I too had a Sunday night phone call, where she was sobbing on the phone saying she couldn’t cope, couldn’t do it anymore.
As a parent it is heartbreaking to hear your child breakdown and not be able to fix it for them, With my DD outwardly I remained calm, sympathised and told her to prioritise sleep and most importantly seek help from her tutor and the uni.
I reassured her it is absolutely normal to feel this way in your first year. yes it feels like the end of the world, especially when you have always been the star pupil, but in reality it’s one or two essays which don’t count towards your final grade, and to try to put it in perspective even though that is incredibly difficult.
Dd got some help and advice from her uni where she learned to prioritise her reading, she logged on a spreadsheet all her time spent studying which helped her to see in black and white how much she was actually doing, and treated her academic work as a job. Every day she structured studying at the library with built in breaks.
We paid for her to join a local gym to help with physical and mental health. she came home almost every weekend in the first year (we were an hours drive so a bit easier) where she was looked after and washing done, meals made. This helped her cope. It got her through and in the second and third years she came home much less and there were less frantic calls.
DD eventually achieved a first but it wasn’t easy and without a lot of support, both from us and her uni she wouldn’t have done it. It needed her to change her mindset, letting go of everything being perfect, managing her time, both in academic terms and self care.
i do hope this goes some way to help, it’s not easy and I wish both you and your son the best.