Agree with XR, that should be temporarily supported on the inside down to a solid base (the main floor framing may or may not be considered adequate enough).
Then that wall should be removed in full and replaced outright. It appears at the gable end, the ceiling joists may be running in the wrong direction, however the rest of the roof appears to have them in the correct direction to avoid this failure, but yet it still appears to have failed. Perhaps the connection between the rafters, ceiling joists and the top of wall were inadequate.
I've seen a lot of shingles stacked on a standard rafter framed roof before, and never to this day have I seen a wall kick out sideways because of it. Until now apparently.
To answer your question, will this stop the wall from pancaking flat to the ground, potentially except that it is highly dependent on the connection between the shoring wall and the existing structure. I would also be requiring a diagonal brace or two on the shoring wall instead of just the blocking. Otherwise that wall can just fold flat.