2009 Toyota Highlander Highlander Hybrid and Rear End Colli

I was stopped waiting to make a left turn onto my street, and a car came up behind me at 50 mph, texting, and hit me square in the rear of the car. His car was totaled. I have a 2009 Toyota Highlander Hybrid. The insurance company of the gent who hit me is saying they can fix the vehicle, which has extensive damage, for around $16K. Damage goes all the way up to the roof support panels over the driver and passenger doors. This repair cost does not include the cost of a new Hybrid battery (which is under the third seat - and saved me from more injury and took much of the crash forces). They do not believe the hybrid battery is damaged. What can be done to insure that the hybrid battery, and the system is going to work? Cost of a hybrid battery and disposal is around $5K, which when added to the repairs, gets pretty close to totaling the vehicle.

To date (it has been a week), they say "the vehicle starts, so the batteries look OK." I do not want them to repair, put it all back together, and then find the hybrid battery needs replacing.

Any suggestion on what I can do to close with them on this issue?