If they permanent resident then u can still get insurance through exchange, if not then apply for visitors insurance. Check with local primary care, they will write a preskription for 20-100 with out insurance.Last option ER...they will not ask any insurance but sent bill later.

Where do you live? PCP’s charge 100 at most in general and medication may be another 100. They also give discounts to patients paying in cash. You may be able to schedule video appointment too. I don’t like the sound of going to ER during middle of pandemic just for continuation of same preskription and potentially exposing your old man to COVID19. Talk to your own PCP and see if he can help.