Of course its a Automatic, his wife drives it :D j/k
I think its the wheel bearings getting old, they drag a bit more and with our automatics its another loss.. Automatics loose efficiency compared to the manuals when they get around 100k miles.. , yes I own both a manual and auto and I see a HUGE difference. You should be getting mid 20s even when car is not running optimal.. I would remove the tires, check for drag on spindals.
I have gotten in to the habit of popping into neutral when I slow down... lowers RPM of engine faster then leaving it in gear and car seems to stop JUST a touch faster, also less drag at a stop on motor.. I see 2 or 3 mpg difference.