Well, when Laurie and I got there, the van was already unloaded and Mom was back off to the rehab place, leaving my brother alone in the yard with big metal platforms, rods, and a bazillion nuts and bolts. After a few abortive moments of trying to help in our work clothes, Laurie and I said, "we'll be back," went home and changed into more serviceable clothes, and picked up a box o' chicken to feed the three of us.
Basically, Laurie attacked the giant tangle of plants obscuring the sidewalk while my brother and I assembled pieces and tweaked and adjusted all the bits until they were all in place with as gentle a slope as we could arrange. Unfortunately, by then it was 9:00 and dark, so we couldn't do the "final touch" bits for lack of light. But the ramp is built, is sturdy, and is usable, and supposedly my dad will be home tomorrow. So here's hoping all will be well. :)