Have had a happy 2008 FEH with over 240K miles. A month ago it started requiring an occasional 2nd or 3rd turn of the key to get it started. Last week it finally didn't start. I got a new 12V and put it in (similar issue was solved this way in 2013). Still it wouldn't start. Brought it into the local Ford dealer and got the dreaded HV failure message and the $9700 price tag to fix. Since I am now a happy 2019 Fusion plug-in driver and my wife has a 2017 plug-in CMax, I don't see any other alternative than donating it.
Sad part was, when the car ran, it was still going into hybrid mode as it had since Day-1 and was still giving me about 36-38 mpg with normal driving, including a lot of highway.
Any suggestions? The dealer said I could keep it at their place for a couple of weeks before moving it (Staten Island).

 

If you are a tinkerer, I would pop the battery open myself and test the cells. It very possibly could be a few cells are damaged and that the rest are fine, as the NiMH batteries these cars use last many many hundreds of thousands of miles.

 

Reportedly you can buy a Salvage battery for $400, or a reman unit for ~$1500, maybe less.
If that car was doing that well on mpg I would be tempted to try that. In fact, my 2008 works fine, and I'm squeezing a bare 27-30 mpg out of it.