I had a Pet Gear tri fold ramp as belldarr.

Unfortunately my BMD is a wimp and didn't like it so decides to leap into the car instead...

The ramp was very sturdy but light weight enough to carry around but I sold mine in the end as he never used it. 2011 4.4 TDV8 Autobiography

I use a folding step for my Golden. That looks very painful.

We recently bought the "Original Petstep" which can be bought in Sand color or Dark Grey and holds up to 250 Kilograms of weight. It folds up in half the size and can easily be placed next to the dog in the back. It has anti-slip rubber pieces on both sides so it doesn't slip of the car or on the ground. Probably one of the best products available and within seconds our border collie was running up and down as if he was in an agility competition

Below link is in Ducth but at least give you an impression how this looks like... Picture happens to be with a FFRR to demo the ramp... http://www.petfooddiscount.nl/dog-step-beige

Really sorry about your dog, hope he recovers soon!! Mike.

2007 Range Rover Vogue TDV8, Black, Sand Leather Seats & Sand / Black Interior.
IID Tool from GAP Diagnostics.