rear end crash advice

[99 ml wc]

Two weeks ago a uninsured man in an escort plowed into my wife's '99 ml320. The escort lost, it's front end was gone. The ML's hatch was smashed but it still opened, and the rear bumper was pushed down and to the left.

The truck spent last week in the best independent body shop in this region having $5200 in body work done.

My Concern:

They were able to bring the bumper support members back into the proper geometry ( they were 70-mm out) but they now have kinks in the frame that can not be removed and my body shop advisor said that they would not have the same structual strength as they did before the crash.

A new frame is $5200 with another $2000 in labor.

The truck has 100,100 miles and is the most base model.
All the normal issues of a '99 model have been repaired.(new transfer case, rings because of early life conventional oil sludging.)

My wife was sold on the car because of its crash ratings to help protect our two young children.

Am I wrong to worry about the kinked Frame?

Should I push my insurance company to total it or push for a new frame or just accept it the way it is?

Any thoughts or advice?