He needs to get form HC1 from your doctors or Jobcentre, some chemists and dentist have them as well.
You can also download one from here, but the ones from the doctor have a pre-paid envelope with them.
https://www.nhs.uk/using-the-nhs/hel...me-scheme-lis/
Fill it in and send it off, they will send back a certificate, HC2, that allows free prescriptions and healthcare usually for a year.
(The can be from six months to five years)
You then renew it as necessary.
If he needs a prescription in the meantime then he will have to pay, but should get a receipt, FP57, from the chemist when he pays.
He can then use that FP57 to get a refund once he has the HC2. (Or can send it with the HC1 application if he already has one).
Can he claim Universal Credit as a student?
https://www.gov.uk/guidance/universa...t-and-students
PS. You might find this post interesting, especially the last paragraph. (Not that I'm suggesting anything).
https://www.youreable.com/forums/sho...l=1#post147431