KDLH will probably work
Three options in the area:
KDLH: Could be the best option for zero hassles at this time of year. About 7 miles away from downtown and the hospitals. "Corporate" style option.
KSUW: In Superior, WI. About 10 miles away, I learned to fly there. FBO owner is fantastic. Better fuel prices and a really nice "GA" airport. Call ahead to see what staffing will look like around the holidays.
KDYT: Sky Harbor. Very neat seaplane/land plane base, 5 miles from downtown. Likely to be somewhat of a ghost town during holidays, but then again give them a call.
WX at all three can be significantly different due to the lake and elevation differences.
When in Duluth, if staying in Canal Park or downtown you'll be within walking distances (mile or so) of the hospitals.
Won't be home from Minneapolis until Thursday or Friday but if that coincides with your trip I could probably meet you at any of the three. Hope your Dad is doing OK.