Sad to hear that. Alteast she has spend her time doing what she loved.
Since Cytokinine production happens in the root tips, i would suspect that the effect is systemic and it does not really matter where its applied.
This study actually compares keiki paste with foliar, but they use 200ppm keiki and 200ppm foliar. So the keiki has little effect in comparison. I guess something like 1000ppm keiki would make more sense in that comparison.