MV6, is dead on correct! These cars must be treated as if you are on a 100+ hp super bike! Nobody sees you, the cabin's blind spots act just like a helmet on a bike, they are very fast and tail happy and will get you going much faster than you can stop quicker than you can spit. If you haven't done any track days with your car, do so. It will slow you down when street driving. I promise.
ROLL CAGE, The front bars that come up from the chassis along the A pillar on my car are there to keep out the minivan in a side impact. The rest is to provide as much bracing as possible to the front hoop. Together, front hoop and top double braces, I would hope will keep out anything I might run under. Of course all this is within REASON. See 1st paragraph.
BELTS, the mounts need to be at least checked out for suitability when used with a 5-6 point harness system . Nice big strong bolts through nice big load spreading mounting plates is a good start. Also the mounting points themselves need to meet the belt manufacturers recommendations. Remember Dale Earnhardt.
FIRE, Start with a on-board fire system and add a handheld. I put mine in to save the car in a rear engine room type problem mainly but one of the two nozzles is also under the dash pointed at the drivers chest.
If anyone knows of a aftermarket fuel cell that would fit in one of our side pods then that would be the most important fire safety addition. If you needed to save money you could put one in in the passenger side for track days and drain the other conventional tank on the other side. 8 gals would be enough for most track day sessions of about 20-30 Min's.
Lastly...... God bless the family and friends in a terrible situation like this one. My prayers are on the way.