sooooooooo.. he wont go to a doctor huh........ hes bascally give up or hes in denial.... either is bad.
MAny peopel do that.. its aphase.. a bad one atthat.
You ahve a few choices. Insteadof pushing teh issue, get avisiting nurse ot ocme out and look at him. Yes there are visiting Nurse practitioners who willd o that> Its a matter of finding one. medicare usually pays. And if he is of age then he cana pply. They can even do that.
You can apply at night either the paint or the cream. make sure he is godo an asleep and do it.

You can use shock therapy by showing him images that you have printed off the system of people who have ignored it.

In any case its ultimately up to him and although its a hard lesson learned, he may have ot get bad to better.
I wil think of other options.. but maybe the visiting nurse practitioner woudl be your best bet. they can prescribe and they can evaluate wihtoutthe need for an office visit.