[darcane]

About three years ago a friend bought a low mile '08 Civic Hybrid at the insistence of her dad to save money. She paid way too much for it, but it got decent mileage.

A little more than a year later, she noticed the fuel economy was dropping, then one day the dash lit up like a Christmas tree and the car died. They took it home and her dad and uncle tried to get it going again, but couldn't, deciding that the IMA battery pack was dead. Neither are mechanics nor know much about hybrids specifically. It now has just over 100k miles.

The car has been parked ever since, as they couldn't afford a new battery pack. She's been borrowing a friend's car since the Civic died.

I'm considering helping her get it running so she can recoup some of her losses.

What is the likely problem? With the batteries being a notorious issue, I suspect that is the likely cause, but surprised that it would suddenly die like that. Any tips for diagnosing?
I'm an experienced amateur mechanic, but have never torn into a hybrid or EV. Am I getting in over my head?
Is it better to just dump the car for whatever she can get as is and not throw good money after bad?