We sometimes get a cabin at one of the few campgrounds open around here in the winter. They have winter seasonal sites. People use them, but it takes a fair amount of prep - especially skirting. And the CG shuts off the water. People with heated tanks fill the fresh water tank and tote the grey water or just use the cg facilities. The water system is the toughest thing in winter.
If your arctic pack includes double pane windows and insulation, that should help keep it warm and reduce condensation issues. Still, you have deal with high propane / electric costs too.
Winter camping is difficult - maybe the clinic has a person that helps families find more reasonably priced accommodations? My mother was in a similar situation last year, so I can relate. Hoping for the best for your father and the family.
2005 F-150 FX4
2013 Rockwood Roo 23 IKSS