the functioning demented alcoholic — "drank himself blind on a daily…"
drank himself blind on a daily basis and then needed at least two hours to sit there naked under a scratchy blanket and shake, and went around impersonating various kinds of health-care professionals during the periods he believed he was a health-care professional, from when he had the delirium-tremen-type career delusions
Context
The fullest single portrait of the disease at its source — the father whose alcoholism the whole inherited-disease thread runs down from. Orin's does-he-function defense inadvertently draws the clinical picture: daily drunkenness to blindness, two hours of naked shaking under a blanket, the delirium-tremens delusions elaborate enough to send him impersonating doctors — all of it running concurrent with founding an academy and inventing anti-fog glass. The point Orin can't see is the one the book keeps making: JOI functioned magnificently and drank himself to the microwave anyway, and the son who'd later name his own tennis-vs-getting-high choice is watching this from inside the same house.