First, Trudy, good luck with your aunt.
I know a little (but only a little) about long-distance drives. When Rigatoni was hospitalized in NYC last year, we did the round trip drive to NYC three times, or about 10 hours for each trip. In my younger days, I also drove to Wisconsin a couple of times (2 9-hour days each way), as well as from Atlanta to DC in one day (about 12 hours).
It isn't bad with a little planning. A thought -- you might want to time your exit from NYC to avoid traffic. If you can leave obscenely early, you can miss a lot of traffic. Say you leave at 4:00 a.m. That should get you to the other side of Philadelphia by 6:30 or so (I assume you're heading down 95 -- if not, ignore most of the rest of this). You can break for breakfast while traffic builds up everywhere and, with luck, be driving through (more or less rural) northeastern Maryland during the worst of rush hour. You might hit the latter part of Baltimore's and DC's rush hours, or you might miss them. (There's a rest stop between the Baltimore and DC Beltways on 95, and another one at around mile 155+/- on 95 in VA.) Gets you past Richmond/Petersburg (which can have some traffic problems) probably around 11:00 or noon. After which there's lots of rural road on both 85 and 95, whichever route you go.
You can still keep your 10-hour day, just end it around 2:00 p.m. or so. That gives you time for an afternoon nap or other rest, a nice relaxed dinner, and a good night's sleep.