How good is this friend? In this "USA" where you live, do you need to do emissions testing? You cannot pass if you have a check engine light and that may be trying to tell you about another problem that could prevent you from registering this car.
Plenty of people register cars at their parents' house, if the parents live somewhere that does not require emissions testing, but I was ticketed for registering my car in a county in which I did not live.
Honestly, the price is a bit of a red flag, it suggests he is trying to get rid of a problem. KBB puts a fair trade-in at $982 and NADA gives a rough trade-in a value of $1150.
NADA: Clean trade-in: $2,425
KBB: Excellent trade-in $1,841
I only list trade-in values because NADA does not show private-party prices. KBB says $2,271 for a private-party sale in fair condition, with a car in excellent condition being worth $3,097. The mileage reduces each NADA estimate by $600.
On-board MPG gauges are usually about 5% overly optimistic, which would suggest he gets around 41 MPG.
Fuel Economy of the 2003 Honda Civic Hybrid rates it at 39/43, 40 combined, and the average user reports 41.3 MPG, so if something is wrong, it is not necessarily affecting mileage.
I recommend taking it to a reputable mechanic for an inspection, but as long as you can register it and take care of whatever it needs, I would say that it sounds like a good deal. If you cannot repair it, you could sell it for parts.
2003 Honda Civic Sedan 4D Hybrid Prices, Values & Civic Sedan 4D Hybrid Price Specs | NADAguides
Kelley Blue Book