BUMP!
Glad to find this thread.
My driver grab bar has broken too, and I have a partial fix and the paracord idea is going to get Incorporated.
So far, I have put a small dowel in between the rubber skin and the broken plastic, I then filled that cavity with high temp hot glue and wrapped the inner part only with black ducktape.
NEXT, thanks to this thread, will wrap with paracord, then put a finishing layer of wrapped leather.
Hopefully when all said and done, it will look good and be comfortable, and I’ll do the passenger side to match.