1999 Jaguar XJ8L

I WAS THE THIRD CAR IN A FIVE-CAR ACCIDENT. I WAS AT A COMPLETE STOP AND ABOUT 0.5 CAR LENGTH FROM THE CAR IN FRONT OF ME WHEN CAR NUMBER 2, A 2004 DODGE DAKOTA PICKUP, HIT ME FROM BEHIND. MY CAR, A 1999 XJ8L, SUSTAINED EXTENSIVE DAMAGE IN THE REAR, BUT ONLY MINOR DAMAGE TO THE FRONT SECTION, NO DAMAGE TO BODY SHEET METAL; ONLY ONE BUMPER SHOCK NEEDS REPLACED. THE DRIVER?????S AIR BAG DID NOT DEPLOY. MY CONCERN IS THAT THE DRIVER?????S SEAT COLLAPSE INTO THE REAR BENCH SEAT. THE POSITION OF MY SEAT WHEN I DRIVE IS; THE BACK ADJUSTMENT IS SET AT OR VERY CLOSE TO STRAIGHT UP (90 DEGREES), THE HEIGHT ADJUSTMENT IS SET ALMOST ALL THE WAY UP, AND THE SEAT DISTANCE FROM THE PEDALS IS VERY CLOSE TO ALL THE WAY BACK. AS A RESULT OF BEING HIT FROM BEHIND, MY BODY WAS THROWN FORWARD ABOUT 10 DEGREES AND WAS WHIPPED BACKWARDS TO A FULL-RECLINED POSITION (ABOUT 175DEGREES). THE ACCIDENT CAUSED MY SEAT TO COLLAPSE INTO THE BACK REAR BENCH SEAT AND AS A RESULT, I WAS IN A FULLY RECLINED POSITION AFTER THE ACCIDENT. IS THE JAGUAR'S FRONT DRIVER'S SEAT DESIGNED TO COLLAPSE? I DID HAVE MY SHOULDER HARNESS AND LAP BELT ON AND THERE WERE NO PASSANGERS IN MY CAR. *NM