2007 X5 4.8 113k for sale, timing chain jumped, thoughts please.

[RonVF]

I am seeking thoughts and information. 2007 X5 4.8 113k for sale, timing chain jumped. Owner was asking $8k, now down to maybe 6k and I was thinking of offering $4k. Vehicle is in great shape with most if not all options.
Owner said wife was driving and it just stopped. Open the oil filler and you can see the chain is off the cam sprocket. My concerns are, is this engine repairable? Hopefully it is just the one bank and would need the head pulled and rebuilt at minimum. Most of the labor I can do however have never pulled a head on an N62n engine or any other BMW engine. ( done lots of Older GM's) I have done a lot of engine work on my 2005 545, Intake, coolant pipe, water pump, secondary air passages, seals etc, but not the timing or head stuff. (She needs valve seals now.. at 182k)
Car would be for my wife who isn't one to pay attention to lights or warnings so my other thoughts are to look for a 3.0 or 3.5 which seems to be less of a maintenance requiring engine.
Thanks for your comments.