Suicidal Dove Chick?

We had a couple of doves try to build a nest on an exterior light fixture, which didn’t work so well.
I put up a solid. level board next to the fixture.
This time, they used the board.
Temps here have been over 100 F, so it was not surprising that the adults started kicking off bits of the nest as the (singleton - one egg was infertile) nestling grew.
Yesterday, the entire nest was on the ground, and mama (and the occasional papa) just cuddled it.
This morning, it is on the ground - without the ability to fly - is has just lost its pin feathers and have a start at flight feathers. No sign of adult coloration except on the edges of the long feathers.
I put a couple of bottles of frozen water near it to cool it off (it was on pavement).
Aside from the first sighting in the AM, neither parent has made an appearance.
I squirted some water down its throat and left it for the parents.
It’s night, we have cats, opossums, and raccoons, all of which would like a snack.
No parents - I heard a dove fly by, but that was it.

I put the chick back on the nest platform with some of the nesting sticks, water, and seed (neither of which it seems to know how to use).
I have a sheet of plastic foam - I went to get it to put under the nest should it come back down.

As soon as I turned my back, the thing jumped off the platform back onto the concrete.
I now have it in a plastic tub with 1" high sides on the nest. With water and seed, I managed to get some water and corn meal down it.

Why would this thing do this, and why did the parents desert it?

There is a pool back there - I once fished a fledgling out of it, took it inside to rinse it off, then put it back in its nest. The parents resumed caring for it, soit’s not like these are afraid of human scent.

Ideas?

If I can find a place to store photos without divulging a userid it wish to keep private, a pic will be available

After 2 days in a food storage container (large enough for a parent to hop in and feed) with walls too high for its gangly legs, I took it out and placed back on its shelf.
Then I took a shower. By the time I got out of the shower, it was back on the ground - head down in the 1/2" gap between the foam pad and the house wall. It hadn’t even managed to land upright, nor had it gotten to getting itself in its only position - sitting on the ground with its legs pulled in under it- it can manage.
Neither parent (who are always around) came to visit.