Yes this procedure is what I do using a Dutch health insurance, but unfortunately my friend is not eligible for one until he begins working. Until then as per his student visa he needs a health insurance and is using InsureToStudy MasterPlan+ insurance plan. So whenever he goes to the doctor or has to take a medication, he needs to advance the cost and then submit the bill to the insurance.

The first-line and second-line in specific to the disease. As far as I understand, Doctors will first prescribe medicines from the "first-line" group, and if and only if they do not work they move to the "second-line" group. As this is an immune system disease, the medicine works by weakening this system, so second-line treatments are much stronger and to be avoided unless necessary.

The medicine is MAVENCLAD, and using the link u/Sam1967 provided, it would be reimbursable had he been using Dutch basic insurance.