The Boeing method seems to be very similar to what has been done with GRP boats for decades, although in a different order, for relatively small damage to hulls.
With a boat, you clean up the hole/damage, usually squaring it off, and then bond a patch on the inside of the hull, but at least 4X its area , so that it overlaps the hole by a lot. The patch is the same thickness as the hull. The patch must follow the curve of the hull precisely, very difficult with a double curve. This patch is the strength of the repair.
A second patch, also the same thickness and curve as the hull but fitting the hole very accurately, is then bonded into the the hole itself. A really skilled worker will reverse scarf it if possible.
The gap is then made invisible with gelcoat matched to the hull.
Insead of pre-manufactured patches, a yard may plug the hole and then lay several layers of GRP to the same strength as the hull over the plug and surrounding GRP, then remove the plug and when the first stage has cured lay more GRP on the outside, in the hole, finishing off with gelcoat over the whole repair. This method is best when the curve makes a pre-made patch impractical.
With a boat, the pressure is from the outside, below the waterline. With the aircraft it is from the inside so this method would be even stronger.