Its partly a question of power. The hybrid Camry gets 200% city & 30% highway better gas mileage. Its a larger car than the Civic, seating 4 larger men comfortably. I'm the smallest at 5'-9" & about 200#. The hybrid real world numbers are double in the city & 1/3 again on the highway compared to the EPA numbers for the 4cyl. model. This improvement comes while still having a net horsepower about halfway between the I4 & the V6 models.
The Civic hybrid gets about 50% better mileage in the city. The current EPA numbers are 36/45 gas only/hybrid.
What engine & vehicle weight does his Civic have? Is it the CVCC? The Camry weighs in at 3680#.
A better comparison is the Toyota Prius. I know two families with three between them that get 50-60mpg. It will seat four & has some cargo room behind the back seat.
His latest model Civic is a 2 door hatchback, it's probably a mid-late 90's. I don't know the engine and weight, but didn't CVCC end in the 80's? It seats 4 (not comfortably), but seems like it compares favorably to the Prius, and yes, it has plenty of power. I don't know the weight, but would estimate it at 2500 lbs or so. I've driven it, and am very impressed with the power and handling. And reliability and longevity of it. I can't see what all the extra money buys when you already have the economy in a car like this.